Game Breaker / Legends of Runeterra

Pre-Launch

Beta

• One of the biggest points of concern to the balance team is the Simple, yet Awesome spell Deny. A lot of the game's strategy is rooted in spell counterplay as players can use strategies heavily dependent on timely use of spells which can then be negated by other spells (such as using Vengeance to kill a powerful enemy unit, only for its controller to use Recall to bounce it to safety back in their hand) but Deny can cut through all that guff simply by cancelling any Slow or Fast spell or even the spell-like abilities of allies such as Anivia's Glacial Storm. While it's limited by its inability to stop Burst spells, which resolve instantly (including almost all buff spells, up to and including the awesome Battle Fury, which are a common "gotcha!" tactic) Deny is still considered far too versatile for its cost and possibly the single best reason to use the entire Ionia faction, as well as a big roadblock to the viable use of expensive top-level spells like The Ruination (if you spend all your mana casting The Ruination only for your opponent to completely nullify it for only 3 mana of their own, you've basically lost on the spot, since you'd only cast The Ruination when it's what you have to do to save the game). In the first major balance patch for the game after the release of the open beta they increased its cost to 4 mana so it can't be cast entirely with stored spell mana.
  • You know it's bad when the few "mono-faction" decks floating around in the early days of the Open Beta meta often find themselves splashing Ionia for nothing more than Deny. It brings in a small risk of missing Allegiance triggers (Allegiance works when the top card of your deck matches the faction of the card being used) but ultimately having Deny is far too useful to give up. Now add to the fact that the Ionia Faction is home to the very frustrating "Elusive" mechanic and it's a lot of pain. Generally you cannot block Elusive units without some of your own so the best way to deal with them are either Challenger Units or Spells. Challenger Units are easily dealt with by just buffing out of range and are rare in their own right, so that leaves spells for most decks to deal with Elusive units but Deny will stop you cold. Many players often say the true game against Ionia (or Ionia-splashing) decks doesn't start until the first Deny is played.
• To elaborate on Elusive a bit, it's basically exactly like Flying from Magic: The Gathering with one significant difference: in Magic every faction had at least some access to Flying creatures^note Green usually doesn't, but this color has plenty of creatures with Reach (can block creatures with Flying) or spells like Plummet (kill any creature with Flying), while in LoR it's a very rare ability almost exclusively concentrated in the Ionia faction. Outside of Ionia, there were only five Followers (Daring Poro, Amateur Aeronaut, the pre-rework version of Jae Medarda, Silverwing Diver and Heimerdinger's Mk3: Floor-B-Gone Turret) and two Champions (Teemo and Ezreal, neither of which are really combat units) with Elusive, two ways to give a unit Elusive (Intrepid Mariner, which can't be used defensively, and Sumpworks Map- you might notice that all but one of the non-Ionian Elusive cards are from Piltover & Zaun) and no cards designed specifically to punish Elusive units (like, say, Hurricane from Magic) or equivalent ability to Reach (a creature ability from Magic that allowed a creature to block Flyers without actually Flying itself). Meanwhile, Ionia has ten Elusive units, several of which are exceedingly deadly. The ability is supposed to function like Flying, but it's so lopsidedly distributed that for all intents and purposes it might as well be "Unblockable". Riot responded by nerfing the stats of several of Ionia's Elusive units quite severely, reducing their ability to kill so you incredibly quickly and making some of them a bit easier to remove.
  • The Rising Tide expansion further mitigated issues with the Ionian stranglehold on Elusive, with Bilgewater containing a considerable number of Elusive units of their own, and giving players another choice of region to use to fight Elusives other than running Ionia. Call of the Mountain also saw the first instance of a "Reach"-equivalent effect in the buff spell Sharpsight, although it hasn't been given its own formal keyword yet.
• Aside from Ionia, Shadow Isles is generally considered the faction closest to being "OP", and a lot of the blame for that is laid at the feet of Elise. A spider rush based around Elise and a bunch of other aggressive spiders such as Frenzied Skitterer can inflict a lot of damage very quickly, and if Elise can be leveled up (very easy to do with a timely House Spider if the opponent can't remove the spiders) they all get Fearsome and Challenger, making effective blocking almost impossible. The first player to reach Master rank said that in his opinion Elusive and Deny were fine, but Elise was definitely too strong. Elise would ultimately go untouched, but the Skitterer would be nerfed from 3/3 to 3/2 and the staple spell Brood Awakening had its cost (which had been buffed from 6 to 5 in patch 0.9.2) reverted back to 6 again in patch 1.2. While Spiders are no longer seen as particularly broken, they remain a fairly potent aggro presence.
  • Also from Shadow Isles, Hecarim is just blatantly overpowered. For its cost, the card just does WAY too much- his attack is for at least a potential 10 damage as he summons two 3/2 Ephemeral followers alongside him every time he attacks, his 4/6 stat line is hard to deal with considering he only costs 6 mana, god help you if he manages to level up (making his Spectral Riders 5/2 by default as well as buffing any other Ephemeral units you use alongside him) and just to ice the cake, he has Overwhelm. Blatantly overloaded, Hecarim was run in practically every Shadow Isles deck without exception by default (rather than just Ephemeral-themed decks as intended) because he was just that broken. In response, Riot nerfed him considerably (reducing his health by 1 and the power of his Spectral Riders to 2) while also giving him a slight compensatory buff (making him slightly easier to level up) so that people would want to level him up and use him to power Ephemeral decks as he was intended to do, rather than just throwing him into every Shadow Isles deck for the raw power of his level 1 form. Eventually this left him a little too weak, so Riot took mercy and gave him +1 power again in patch 1.2. Ironically, he ended up being left behind so much by Power Creep that in the 2.11.0 patch they actually buffed him again to 5/6, even stronger than he was on launch, which is still not considered to be enough to make him viable!^note He generally takes up your entire turn 6 mana allotment to play, but if you don't get his first attack off, because he either gets removed or stunned, he just leads to a crippling tempo loss.
  • In addition to overpowered Champions, Shadow Isles also boasted an insane card draw tool in the form of Glimpse Beyond, which trades 2 mana and one of your units for two cards. This sounds okay at first until you consider that it was initially a Burst spell, meaning that it can be chained to any removal spell or bad trade to draw 2 for virtually no cost at all (by killing a unit that was about to die anyway) while wasting the opponent's card or attack, and the opponent wouldn't be able to do a thing about it. Glimpse quickly became a guaranteed three-of for every Shadow Isles deck, and Riot quickly learned to never again print a card that removes units from the board at Burst speed. Glimpse Beyond was duly nerfed from Burst to Fast, giving the opponent a chance to counter it as removing Glimpse's target causes it to fizzle.
• Fiora is an extremely powerful champion card that can set up numerous instant win scenarios. Her main gimmick is that if she kills four enemies total, Fiora will instantly end the game in a victory for her side. This is the only Instant-Win Condition effect in the entire game (until Call of the Mountain introduced Star Spring), and thanks to her Challenger effect Fiora can drag opponents out to fight her by force, making it very difficult and potentially costly to attempt to dodge combat with her. Build her up with a Shen for Barriers and a few other cards and wham, you have a borderline invincible card with a time limit on ending the game. While she comes with noticable weaknesses (she's quite fragile and thus can easily be taken out if you're not careful, and her win condition is basically impossible to trigger against slower decks with bigger units) there are simply so many ways to mitigate her most glaring flaws that a number of the strongest setups in the game (especially ones reliant on Zerg Rush tactics like the aforementioned Elise deck) can regret staffing their ranks with weak units. And god help you if she gets her hands on a "Judgement" spell card, since every kill she makes with it counts towards her victory total. She remained a constant presence in the game for more than a year before finally having her HP reduced by 1 in patch 2.5- as a result, you'll still find the occasional player using her in a deck entirely built around protecting her, but she no longer is splashed willy-nilly into any Demacia deck that doesn't require other champions, as her statline is now considerably worse than the Laurent Protege. She would much later be burfed to a 4-mana 4/4, making her harder to kill but giving aggro decks an extra turn to put up a fight.
• Elnuk decks are considered borderline coinflips in execution. They revolve around the (supposedly) Difficult, but Awesome Troop of Elnuks, which when played summons every Elnuk in the top ten cards of your deck. The main problem with this card is that the card's value is potentially absolutely insane for its cost. The Troop isn't a great body on its own, being a 3/3 with no combat abilities for 5 mana, but if you hit multiple Bull Elnuks (a 4/5 with no abilities, still a beefy unit to get for free) or even extra copies of Troop, you can suddenly have a massive advantage over your opponent- if you hit nothing, you're boned because of the tempo loss, but the odds are generally in your favour to hit at least one other Elnuk. Troop of Elnuks is considered to be an extremely unbalanced card that is simply too potentially valuable to ignore, and has been heavily criticized for its RNG-heavy nature in a game that has been lauded for mostly minimising card game RNG. The archetype got heavily nerfed when Troop was reduced from searching the top 10 cards of the deck to searching the top 6 instead, considerably reducing its consistency when you only run 3 Troop of Elnuks and 3 Bull Elnuks, intending for it to only be used in specialised Counterfeit Copies-based decks rather than automatically splashed into every Freljord deck by default.
• After the first few rounds of balance tweaks, it was generally agreed that the most influential card in the game was actually the innocuous little follower Vanguard Bannerman, a Demacian unit whose Allegiance^note triggers an effect on play if the top card of your deck is the same faction as this one effect gives all your units +1/+1. A simple enough effect, but Allegiance proved to be a rather dodgy mechanic as, rather than having a random chance of working but being very powerful when it did, it instead just encouraged people to build mono-faction (or mostly mono-faction with just a splash of another) decks to capitalise on their over-efficient effects, with Bannerman the most unbalancing. Mono-Demacia decks would cleanly curve up into a strong board of efficient followers like Fleetfeather Tracker into Brightsteel Protector or War Chefs into Laurent Protege or Fiora, then slap down a ridiculously over-efficient Bannerman to gain total control of the board. It would follow up with Garen and Cithria the Bold, backed up with spells like Single Combat or Riposte, and then the game would pretty much be over. It may not sound like anything special, but it simply became flat-out the strongest deck in the entire game- tournaments were held where literally almost every player was running some variant on the Bannerman deck (some with Noxus for the efficiency of House Spider, some with Ionia for the safety of Deny, some just straight mono-Demacia), and even when popular streamer MegaMogwai went into a tournament with his entire strategy being to run anti-Bannerman decks^note  The format of the tournament saw every player bring 3 decks, of which their opponent could choose one to ban, and the winner was the first one to win a game with both of their remaining two decks- Mogwai correctly predicted that every player would bring a Bannerman deck and specifically built all three of his decks to prevent them from winning with it he still ended up failing at the last hurdle to a Bannerman deck because the archetype is simply too strong against all possible match-ups. Riot responded by giving the card a minute nerf that causes it to no longer buff itself, making it only a 4-mana 3/3 instead of 4/4, but this isn't expected to really make much of a difference, with most players banking on the release of the first expansion instead.

Post-Launch

Rising Tides

• In the post-launch meta, the most powerful deck has, rather aggravatingly, come to be Noxus/Piltover & Zaun face burn, using Boomcrew Rookie, Get Excited!, Mystic Shot, Used Cask Salesman from P&Z and all the Noxian cheap weenie followers, unit buffs and Decimate to simply smash the opponent to death in 5-6 rounds at most. Most variants don't even bother using Champions (even Darius, who was made for this sort of deck, is considered too slow to bother with) although some run Draven or very occasionally Jinx. The deck is frustrating and unfun to play against as it's boring, one-dimensional, simplistically mindless and as non-interactive as a deck in LoR can be, and only decks with ridiculous amounts of chump blockers, efficient removal and life gain really have a chance against it unless the burn player gets a really screwed-up hand. Plus for some infuriating reason, burn players always seem to both get to go first and draw the stupidly over-efficient Legion Rearguard in their opening hand, which usually means 3 unavoidable damage on the first turn. The Boomcrew Rookie is usually held up as the chief offender in the deck, as it's just too efficient and (unlike the Rearguard) too hard to deal with- it's too cheap at 2 mana, its 4 health means it resists ALL cost-efficient removal spells and can survive almost any blocker of comparable cost, and its attack skill means that even if you block it you still take 2 damage even before combat commences. Even decks specifically designed to punish the burn have to play perfectly and be very lucky to win against it. Riot took measures to reign it in with the first post-launch balance patch reducing the health of both the Legion Rearguard and the Boomcrew Rookie by 1, making them much easier to remove. The deck has so far survived, though most versions now swap in Teemo instead of Legion Rearguard.
• Also post-launch, Vi rapidly proved herself to be the new Hecarim- a champion so all-round powerful that she would be thrown into any Piltover & Zaun deck with room for her because there was no reason not to use her. Her combination of Challenger, Tough, relatively high health (considerably enhanced by the Tough), a power that was very easy to pump up to ridiculously high levels, a devastating ability in her level 2 form and a perfectly affordable mana cost meant that she could single out and destroy basically any enemy unit with relative ease and walk away from it, and once she leveled up she'd destroy the enemy Nexus in short order at the same time. Even mono-faction decks (like the aforementioned Bannerman deck, which is still hanging around the meta) would splash in Piltover & Zaun solely to use her. Again, Riot nerfed her on the first post-launch patch by reducing her health by 1 (which is a big difference for units with Tough).
• It doesn't come much more broken than Unyielding Spirit. Which makes a chosen unit completely invincible. And we do mean COMPLETELY. As in no card, unit, champion or spell is capable of killing the recipient. Being a burst spell, it's even immune to Deny. And if affixed to a champion card, is immune to Purify. The only possible counter is a card with the Recall ability, which are few and far between. Riot nerfed it in the 1.4 patch by changing it from Burst to Fast speed, allowing players to respond to it with removal before it can resolve.
  • It's also getting a much more significant nerf with the release of the Targon expansion, which adds several more Silence effects to the game that can negate it.
• They Who Endure, a 6-mana 1/1 unit that gains an additional +1/+1 in deck or in hand whenever any ally, anywhere dies as well as Overwhelm. In normal decks TWE will end up with respectable stats when you're ready to play it, but when combined with Shadow Isles which absolutely spams self-unit deaths as well as the crucial spell of Atrocity, a card that lets you sacrifice one of your own units to deal its power to anything, including the enemy nexus, and you get a game-winning package all on its own in just two cards. So when you take a 16/16 They Who Endure and slam it into your enemy's nexus with Atrocity, you get a powerful and difficult to prepare for finisher. Even worse, Atrocity is a Fast spell, so you can just attack normally with the massive They Who Endure to try and crush your opponent underfoot, and save Atrocity to counter when they try and respond with something like Vengeance. This combo has actually been in the game since the beginning, but it wasn't a Game Breaker, until...
  • TWE has always had decks built around it, but it wasn't until the Rising Tides expansion that the Shadow Isles and Freljord combination got some much-needed midrange tools for it to play around with in Blighted Caretaker and Neverglade Collector. These two cards combined gave TWE decks both the ability to trade up into enemy units offensively rather than just spamming blockers and praying to Jesus that you would get a TWE + Atrocity package up in time before your opponent managed to put together an answer for your Atrocity finisher. Neverglade Collector combined with the death-spamming nature of your deck puts some real pressure on your opponent's nexus and is a mid-game finisher in of itself, while Blighted Caretaker lets you kill a unit you own, which often leads to another side benefit, to spawn two challenger Saplings, letting you handle key enemies with targeted precision. Riot nerfed They Who Endure's mana cost from 6 to 7 in the 1.4 patch.

Call of the Mountain

• After he saw mixed use following his release in Rising Tides, in the 1.10 patch Riot (perhaps typically, based on his track record in League) gave Lee Sin a colossal buff, changing him from a 6-mana 3/6 to a 4-mana 3/4 (and also changing his signature spell from the useless Dragon's Rage to the quite useful -especially for Lee Sin- Sonic Wave), while also slightly nerfing his level-up requirement. Now as anyone who knows anything about card games could tell you, changing a unit's stats by 1 or 2 points can be a pretty big deal, altering the spectrum of what it enemies it can kill and how much damage it can survive, but altering a card's cost is a far greater change, able to turn a card from worthless to game-breaking at a single stroke. Reducing Lee's health by 2 wasn't even vaguely close to being an even trade for him being able to hit the board 2 full turns sooner than he used to, and considering that he had the ability to (quite easily) give himself Barrier every turn if his deck was constructed even remotely properly, the loss of health barely affected his survival at all. As a result, changing from a mid-late game champion to an early-mid game one made Lee a holy terror, almost impossible to remove and capable of picking off enemy units with ease, before leveling up and using his free Dragon's Rage combined with spells that gave him Overwhelm and some attack buffs to OTK the enemy player. The deck had few counters outside of Frostbites and was almost universally considered meta-warpingly overpowered, leading to players desperately awaiting the next round of balance changes that would bring him back into line again. Unfortunately, the 1.11 patch notes not only didn't do anything to Lee, Riot instead chose to give the protective Burst spell Bastion a huge buff, changing from a 3-mana spell that gave an ally Spellshield for 1 turn, to instead granting a unit +1/+1 and a permanent Spellshield that now wouldn't expire and had to be popped manually. Since Lee decks were often using Targon already for its array of buffs, this took Lee from "overpowered" to "almost invincible" as a preemptive Bastion meant that not only did Lee become even bigger, but now you couldn't even Frostbite him any more (unless you had another expendable spell to waste popping the shield). Community outrage was spectacular, and when the only change Riot made in the next patch was to increase the now appallingly overpowered Bastion's cost from 3 to 4 and still not do anything to Lee Sin, some players just gave up in despair. Eventually Riot caved in and partially reverted his initial buff, changing him to 5 HP for 5 mana.
• While Aurelion Sol was intended to be Difficult, but Awesome, parts of his kit turned out going too far and ended up getting nerfed.
  • Cosmic Inspiration gives a permanent +2/+2 buff to all units you have or will have played this game, for what seems like a price of skipping a whole turn as well as needing another celestial to trigger... But originally it refunded 3 spell mana, turning its effective cost from 7 down to 4 and allowing you to still play some spells afterwards. Nerfs removed that refund.
  • Living Legends is an immensely powerful effect as intended, refunding its mana cost and giving a bunch of potentially very powerful cards. With levelled up Aurelion Sol on board it is basically a guaranteed win, but even without him it used to give you more mana than it cost in the first place. This over-abundant refund has been removed as well - it now only refills your crystal mana, not your spell mana.
  • Aurelion Sol himself was found out to be a tad too easy to level up, often needing only himself and just one more of the high end Celestials - with both having Spell Shield rendering them way too hard to remove (especially with Eclipse Dragon on turn 7 curving into Aurelion Sol on turn 8). The requirement went up in a patch from 20 Power on your board to 25, making it nigh impossible to hit with just 2 units and thus needing you to set up more to trigger (this was later reverted in Beyond the Bandlewood due to Dragons falling off in viability).
• Pale Cascade seemed like an innocuous enough little spell, a Burst-speed buff spell that gave a unit +2/+1 for the round and drew its controller a card if Nightfall was triggered. Unfortunately, it rapidly became jarringly obvious that it was hands-down the best buff in the game because the card draw negates the biggest drawback of buff spells- that using a buff spell expends card advantage to tip a trade (buffing a small unit to kill a larger one means you're still trading 2 cards for 1). Combined with its cost-effective damage boost that allowed Targon decks to trade too favourably it was just too efficient, and Riot eventually had to nerf it down to only giving +1/+1 in patch 2.1.
• Hush is a 3-mana Burst spell for Targon that Silences a unit for one round. Any unit, including Champions, which made it incredibly widely reviled for simply nipping unit- and buff-centric strategies in the bud or even denying a Level Up. This was particularly bad with its initial incarnation, which created a Fleeting copy of itself in hand to shut down even area buffs, and it was duly nerfed to generate a Fleeting copy that costed 1 more before that aspect of the spell was removed completely. However, it also got a compensatory buff to 2 mana, which meant it was still just as problematic and ubiquitous as ever. Riot eventually just nerfed Hush back up to 3 mana after it became apparent that every Targon deck was running it to punish buffs and neuter champions, and even after that, people are still wary of buffing against Targon.

Empires of the Ascended

• Remember Atrocity and Blighted Caretaker from the They Who Endure package? They quickly found a new best friend in Nasus, who builds up in much the same way and tends to hit cosmically huge Power values just as easily. All you have to do to build him up is to kill as many units as possible, which is something that Shadow Isles thrives on doing. Blighted Caretaker contributes to this in a major way with its effect, which blows up one of your own Units and summons two tokens with Challenger for more fodder or picking off weak enemies. Even better, Nasus being a Champion means that a levelled Thresh can cheat an attacking Nasus right out of the deck, ready to smash the opponent for enough damage to level up on the spot more often than not, gaining a Spell Shield and often leaving the opponent one Atrocity away from game. Riot deemed this deck too oppressive and nerfed Atrocity from 6 to 7 mana while axing the Caretaker's stats from 2/1 to 1/1, slowing down the deck's finisher while reducing the amount of advantage a Blighted Caretaker can generate. This still wasn't enough to fully bring the deck back in line, so in the 2.11.0 patch Nasus was nerfed so that his level 1 form no longer has Fearsome until it levels up (making it possibly to chump block him with a weak unit and then remove it yourself to prevent him from striking it to level up) and the oppressive Escaped Abomination was nerfed for the second time from 4/3 to 4/2, considerably weakening the deck's early tempo and board control.
• By the time "Guardians of the Ancient" was released, Riot had determined that Shurima was underperforming, being a region with a strong focus on Combos but only being used for its aggro cards like Dunekeeper and Azir. Their attempt to rectify this problem, however, was simply to release a Purposefully Overpowered follower in the new set- Merciless Hunter, a shamelessly broken card with a premium statline for its cost (4/3 for 3 mana), a powerful keyword (Fearsome) and an exceptionally powerful ability (permanently granting Vulnerable to any enemy unit of your choice when you play it). This was considered an incredibly lazy and misguided solution to Shurima's problems; when leading community member MegaMogwai posted his thoughts about fixing the badly broken meta, he pointed out that this common follower was Strictly Better than Kalista, a Shadow Isles champion, as well as asking what the hell Riot were doing by releasing the interesting but slow Shurima champion Zilean in the exact same set of cards as a card that hard counters him on the turn after he's played, able to grant him Vulnerable and then instantly kill him on attack without even trading. The card is a 3x auto-include in every single Shurima deck other than, ironically, the meta-defining Azir-Irelia deck (since Azir and Irelia are both 3-drops as well, and the deck doesn't need it anyway since it's a combo deck that overwhelms opponents in a hail of token units without caring about removal) and is considered one of Riot's biggest design blunders. In the "Beyond the Bandlewood" release patch the Hunter, along with its equally-overtuned accomplice the Ruin Runner and the overpowered buff spell Shaped Stone, were all collectively nerfed (largely as a result of their meta-dominating performance in the freshly-buffed Sivir's decks), with the followers both losing -1 health and Shaped Stone's conditional power buff being reduced from +3 to +2. However players were still bothered by the fact that, although the Hunter was now easier to remove with spells, it still traded positively on its own against units like the 4-mana 1/4 engine Champions Maokai and Veigar.
• Speaking of Azir and Irelia, they very quickly became the deck to beat on the ladder, thanks to the terrific synergies enabled by the Blade Dance keyword used by Irelia and her followers. Blade Dance, for the uninitiated, spawns 1/1 Blades to perform free attacks on the enemy (as in, attacks that don't require or consume your Attack Token), synergizing frighteningly well with too many Ionian and Shuriman cards to count. Azir and Emperor's Dais spit out Sand Soldiers to supplement the onslaught of Blades, Level 2 Azir and Inspiring Marshal buff them into legitimate threats that must be blocked lest the player lose most of their health (which also weakens potential comebacks if done on the opponent's turn or just softens enemies up for the next wave), Sparring Student and Greenglade Duo turn into gigantic beatsticks, and so on and so forth. The flurry of Blades also makes it trivially easy to level up Azir, and Irelia's condition isn't a whole lot more difficult, turning Azir into a buff dispenser and Irelia into a nigh-unblockable menace. Put all this together, and you get an aggro/combo deck that can easily tear through boards and the opposing Nexus in a single power turn. Patch 2.9 addressed the dominant status of the deck by nerfing the mana costs of both Inspiring Marshal and Blossoming Blade by 1 mana apiece (up to 6 and 5 respectively), making it slower for the deck to line up a killshot without inflicting collateral damage by targeting the champions as well as nerfing the Marshal's HP by 1 and giving the Blade a compensatory +1 power buff. However, the general consensus was that this would have minimal effect on the deck (and the Inspiring Marshal nerf, while significant, would hurt Azir/Lucian decks more, something Riot had specifically said they wanted to avoid, while Azirelia players simply replaced it with Voice of the Risen anyway now that the 4-drop slot was left open by the nerf to the Blossoming Blade, maintaining a flawless curve) and patch 2.9 was the most weaksauce patch in the game's history.
  • To fully understand how absurdly overpowered the "Azirelia" deck is, over a sample of 64,000 games, 28% of players were playing it- over a quarter of all players in the game! And despite having given the community time to formulate counters for the deck (with the result that the entire meta came to be warped around it, like a crashed car wrapped around a power pole), it still managed to maintain a win rate of 55%. As a result, it completely pushed any deck that wasn't optimised to deal with it (e.g Deep) out of the meta completely. Riot's patch notes, which suggested that the deck had seen a "rise and fall in popularity and efficacy" were criticised for trying to sweep the problem under the rug, as the consensus was that the deck had had a monumental rise, followed by only a slight fall to still be exceedingly meta-dominant even when the entire meta revolved around it. In the 2.11.0 patch accompanying the 'Rise of the Underworlds' set, Riot nerfed both Azir's and Irelia's level-up requirements, from 10 summons to 13 and 12 attacks to 14 respectively, delaying the deck's unstoppable power spike for one (hopefully) crucial turn, as well as swapping the stats of the Dunekeeper from 2/1 to 1/2 and removing Attune from the Dancing Droplet, although a lot of people were disappointed that absolutely nothing was done to nerf Blade Dance itself, or to make it possible for Azir to be removed cost-effectively by any card other than Culling Strike.
• Even before there was Azir and Irelia, there was another deck that found itself heavily dominating the game to the point that it has eliminated an entire playstyle from the meta. That deck being Lissandra Trundle Control, abbreviated (perhaps quite ironically) as TLC. Combining the familiar packages of Shadow Isles and Freljord for stalling prowess with new tools such as Blighted Ravine and Three Sisters to stay alive and maintain control of the field so as to take advantage of a truly fiendish combo. Ideally, Lissandra is supposed to be centered around accelerating the countdown of her thralls in order to level up. Instead, TLC focuses on Trundle and his Ice Pillar. By combining Ice Pillar- which refills 8 mana upon being summoned- with Fading Memories, a 0-cost burst spell, it's possible to summon two eight cost units and level up Lissandra while still having full mana. On its own this wouldn't be so bad if it weren't for Spectral Matron, which summons an ephemeral copy of any ally in hand upon being played. This includes The Watcher. And because The Watcher's original cost is a whopping 17, the combination of two Ice Pillars Spectral Matron's effect means that now the original version of The Watcher now costs zero mana. Because its stats make it nigh-impossible to kill The Watcher without direct kill/obliterate effects, combined with additional copies of Fading Memories, TLC currently the definitive control deck that, if played well, can be guaranteed to win the game on Round 8 or 9 unless you manage to destroy their Nexus beforehand. Because of this literally no other control decks are able to be meta, as none of them are as fast or able to end a game as reliably as TLC. This arguably even feeds into the Azir/Irelia problem above, because it means no other control decks can develop to counter Azir/Irelia without being consumed by TLC instead.
  • What makes TLC so abysmally toxic and degenerate is that the entire deck is based completely around edge-case abuses of cards in ways the design team never thought of. As mentioned, Lissandra is supposed to be the queen of a horde of Frozen Thralls, playing a slow, defensive game while building up her forces before crushing the opponent in a storm of Overwhelm units with The Watcher as her late-game nuclear option when even that isn't enough; instead her one and only role in the deck is "generate The Watcher". Trundle is supposed to be a brutal beatstick who smashes through enemy lines with his ever-ramping power, using Ice Pillar to single out the weakest enemies either to remove them or just to stampede over them with Overwhelm for easy face damage; instead his only role in the deck is "generate Ice Pillar then function as a meat shield to stall for time", while Ice Pillar's role is "level up Lissandra unfairly easily". Spectral Matron is supposed to provide a tempo trade-off by playing an underpowered-for-cost unit (a 6/6 with Fearsome for 8 mana) while also generating additional temporary power in the form of another powerful but Ephemeral unit at the same time; instead people have abused her ability to trigger Summon effects of what are supposed to be powerful late-game threats (not only The Watcher, but also Cithria, Lady of Clouds in another far less meta-dominant but still irritating deck) far earlier than they should be able to be triggered, reducing its role to "cheat The Watcher into play". And as already mentioned, The Watcher, intended to be a Lissandra deck's single-use ultimate sanction for breaking stalemates between control decks, has been reduced to "win the game on turn 8 or 9, no questions asked". There are ways to survive the deck's win condition (killing The Watcher before it can attack or stalling the Ephemeral copies by either stunning or Hushing them so they expire without triggering their attack effect) but the number of redundancies built into the deck and the sheer remorseless reliability of its combo makes it one of the most toxic decks the game has ever seen. The deck was quite severely nerfed in the same 2.11.0 patch that attempted to reign in Azirelia, with The Watcher's ability changed to only Obliterating all but three non-Champion cards in the opponent's deck, leaving them at least two turns worth of attacks (assuming they don't accidentally draw an additional card), and making its cost-reduction effect require the playing of five 8+ mana units rather than 4, meaning the copy you cheat into play with the Spectral Matron is no longer sufficient to make the real copy free. As the deck is entirely based around accomplishing its combo at any cost and has no secondary win condition, the removal of its almost-guaranteed Instant-Win Condition killed the deck altogether, to the great relief of most of the player base.

Beyond the Bandlewood

• The Arsenal had a short stint due to a buggy interaction. As he gains keywords via an aura rather than the usual "grant" mechanic, it meant that his Spellshield keyword would immediately refresh whenever he'd lose it. Add up a few other keywords such as Scout and Elusive for unblockable damage twice a round, and Lifesteal to catch your own nexus health up, and getting him on the board resulted in an unrecoverable swing of the game state. He has been since addressed in a patch that removed the invulnerable shielding.
• From the instant it was first revealed, Aloof Travelers was dreaded as the most toxic card the game had seen to date. At the base level, its primary ability is disgustingly powerful- forcing the opponent to draw a card (intended to synergise with trap decks) and then forcing them to discard their most-expensive card, which was expected to be crippling against late-game control decks by forcing them to discard their win conditions like Aurelion Sol, The Harrowing, or Feel The Rush, as well as irritatingly powerful against midrange decks as well (especially since, unlike similar effects, Champions have no protection against being discarded). At only 4 mana it hits the board far too early for control decks to be able to do anything about it at all other than hope they don't draw their win condition before they're ready to be played. Making matters worse, it's a summoning effect rather than a play skill, not allowing the opponent to react to it before they lose the card, and it would even trigger if the card was brought into play by other effects (such as returning from Ancient Hourglass). Worse still, it also draws its controller a card (without forcing them to discard as well), meaning they don't even lose any card value whatsoever for playing them, a secondary effect that serves no purpose other than to make the Travelers even more busted than they already are. An underestimated facet of the card's design is that it is also dual region (Bandle City/Piltover & Zaun) for no real reason^note while it's technically designed to synergise with trap decks, a lot of new trap-synergy cards in Beyond the Bandlewood, such as Lecturing Yordle and Ava Achiever, which have a far more explicit synergy with the archetype, are mono-Bandle City, while thematically the Travelers have no specific connection to P&Z, just accompanying Teemo's Bandle City Scout troop like the aforementioned Ava, which not only means it can be run in every P&Z deck regardless of whether or not it's paired with Bandle City (and it was), but extra copies can be generated by the likes of Bandle City Mayor and Loping Telescope, with the former also discounting its already far-too-reasonable mana cost to disgustingly cheap levels. Finally, despite all of this power, it was just revoltingly undercosted and overstatted- a 4-mana 3/4 is considered below-par^note the standard price for a 3/4 is 3 mana but perfectly acceptable if it comes with a useful ability, and as already made clear the Travelers had the most disgusting ability in the game. Literally every single deck using either Bandle City or Piltover & Zaun ran 3 copies absolutely without question because there was simply no drawback to the card at all and it could single-handedly win you the game as soon as you played it if it knocked out the right card. Riot eventually nerfed it down to a 2/3 for 4 mana, which is just a bit too far below par for its cost for it to remain an automatic 3-of in every deck, but it continued to see use in some decks, as well as remaining a particularly toxic presence in the aforementioned cases where the Mayor Manifested it and let it be played for 3 mana (or less with multiple Mayors).
• Another particularly gross card from the set was Lost Soul, the backbone of the Sion-Draven discard strategy. While its stats are beyond terrible, it wasn't ever used for its stats, because when discarded it added a Twinblade Revenant to your hand - a disgustingly powerful 4/3 Challenger for 4 that adds a Lost Soul to your hand when it dies. This thing was essentially Merciless Hunter 2.0; its ridiculous statline meant that it could trade up against most champions and support followers in its range, and even if it died in the process, it just replaces itself. More to the point, it almost completely removed the actual cost element to discard-based effects, letting you freely abuse them without the loss of any actual card value; for example it makes Zaunite Urchin simply the best 1-drop in the game, giving you a 1-mana 2/1 body AND a free card draw with no additional cost. If a discard deck opens with Lost Soul in hand, chances are it will carry the game for them. Twinblade Revenant eventually got a well-warranted nerf by replacing its Challenger keyword with Fearsome, taking away a lot of its trading and value-generating power (the same patch also dropped Draven from 3 health to 2, just to take Discard Midrange down another peg). The deck's power play, Sion, also had his Power cut by 2 whole points (reducing his level 1 from 3 base power to 1 and his level 2 from 10 to 8), which would later be partially reverted, bringing him up to 2 and 9 power, after Discard Midrange finally fell out of the meta.
• One of the major culprits of Bandle City's initial dominance was Poppy, initially a 4-mana 4/3 that gave all allies with equal or less power than her - and herself - a permanent +1/+1 whenever she attacks. Combined with Bandle City's ability to vomit units (and perhaps paired with another region capable of the same), this made Poppy a deadly snowballing threat if she couldn't be taken off the board immediately before she gets to attack, which often demanded some heavy-duty removal and made Poppy the core of some extremely powerful midrange decks. Riot was forced to punish her harshly with the nerfbat by cutting her Power from 4 down to first 3, then to 2, realigning her with her intended purpose of buffing up boards of weenies, rather than pushing mid-sized units up into huge threats. She also lost the ability to buff herself, preventing her from snowballing out of control.
• Out of all the Formidable cards introduced with Galio, Petricite Broadwing was very quickly singled out as the most busted. Because Formidable causes a unit to strike using Health instead of Power, this card was essentially a 2-mana 3/3 Challenger that was immune to Frostbite and other Power drops - way above the mana curve and more than enough to trade up with anything in its weight class, and the only common removal spells capable of efficiently killing it cost more than Broadwing itself. Even though Formidable also means it gets weaker as it takes damage, its initial power still meant that it was nearly impossible to efficiently contest a Petricite Broadwing on-curve. No Demacia deck left home without three copies of it. Eventually, Petricite Broadwing received the same nerf that fellow problematic bird Fleetfeather Tracker did back in beta, namely making it only gain Challenger after seeing another ally being summoned.
• Buried Sun Disc is a 1-mana Landmark with a 25-round Countdown, and the crux of the mono-Shurima playstyle to unlock the Ascended Champions' Level 3 forms once its Countdown completes. Originally, it drew itself from your deck and advanced 10 rounds each time you leveled up an Ascended Champion, and in this state it was mostly a novelty for making your opponent sit through a ton of Level Up animations when you cast Ascended's Rise since the Ascended Champions available were rather tough to Level Up otherwise (aside from Azir, who wouldn't complete the countdown by himself). Then the Sun Disc was buffed to put itself on the field instead of in your hand, meaning that you get it for free and thus have 1 extra mana to spend on a 1-drop or bank for spells, and Azir was buffed to count Landmarks in addition to units for his Level Up condition. These changes made the Sun Disc much more consistent and easy to complete, particularly since Azir now synergizes with the new Ascended Xerath who also gave the deck some much needed board control when paired with a Landmark package. This made it possible to complete the Sun Disc long before most opponents were prepared to deal with Xerath's massive damage and the pressure from the Emperor's Deck. To rein in the Ascended's dominance, Buried Sun Disc was nerfed to advance by 9 rounds instead of 10 when you Level Up an Ascended Champion, giving opponents a couple more turns to deal with them.

Worldwalker

• Of the champions released in "Worldwalker", it didn't take long for people to zero in on the initially unassuming-seeming Bard and his Chime package as the most useful- unfortunately in a way that was absolutely toxic and broken. The second Runeterra Champion, Bard demonstrated the primary flaw in the concept's execution by basically being a single-Champion region whose package of overly-efficient cheap minions (Byrd, The Bellringer and Esmus, Breath of the World, with the other Chime cards being ignored) could be slotted along with Bard into any mono-region single-Champion deck to unfairly enhance all the other units with random Chimes that made them unreasonably oversized for their cost with zero effort, which was particularly unfair when the passive effect of Bard's Origin, The Wandering Caretaker, gave you Chimes in the first few turns without you even having to lift a finger. Bard himself was effectively a win condition in his own right if you managed to level him up (which was unreasonably easy for certain factions with wide-reaching buffs like For Demacia!), letting you easily pump your live board up to even bigger levels as you drew more and more Chimes, and the the sheer RNG-based variance of the deck made it one of the most frustrating decks to play against. The most-dominant version was Bard/Illaoi, which was just too oppressive with the already-durable Illaoi buffed out of reach of most removal by Chimes and the Spawn mechanic making Bard easy to level up, since every time a Tentacle grew from Spawn it counted 2 points towards his level requirement. Riot eventually gave Bard a minor nerf in the balance patch leading up to the reveal of "Awakening", making it so The Wandering Caretaker doesn't start stuffing your deck with 3 free Chimes per round until round 3 at least, but a lot of people still weren't happy with it, and he remained ubiquitous.
• "Forces from Beyond" was considered something of a letdown release because of lopsided Champion power- Gwen was interesting and fun but not balanced properly to really make a serious impact on the competitive scene, Evelynn was so bad she was completely unplayable, and Kai'Sa (who, like Bard, initially seemed modest enough) was the most-busted, meta-dominating Champion since the bad old days of Azirelia, largely due to a single subtle but jarringly-massive design oversight- her new keyword, Evolve (give all Evolve units +2/+2 once you've had units with 6 other keywords in the game), which also doubled as her level-up requirement, was trivially easy to activate. Riot forgot how many cheap units with more than 1 keyword they'd released in Demacia (most notably Valor and the Greenfang Warden, both of which came with Scout, a keyword so powerful it had to be specifically removed from the pool of random keywords that units could gain, with special mention also going to the aforementioned Petricite Broadwing which also contributes Formidable toward the total) and Kai'Sa's own signature spell, Supercharge, was quite simply nauseatingly overpowered in its own right. The meta was completely overtaken by Shurima/Demacia single-Champion Kai'Sa decks where Evolve would be triggered by turn 4 or 5 at most, Kai'Sa would almost invariably be played on turn 5 (or turn 6 at latest if they didn't draw her and had to use Rite of Calling to burn a mana gem to look for her) at level 2, immediately gain Scout and Challenger from Second Skin being played on a Valor then Overwhelm and Spellshield from Supercharge cast with spell mana, and then double attack to basically wipe out your board and smash your face and there was almost nothing anyone could do about it. The entire meta ended up reduced to the mono-Kai'Sa decks and the aforementioned Bard/Illaoi decks (calling back to "Empires of the Ascended" when the meta had been reduced to Azirelia vs TLC) and in the same patch where they nerfed Bard Riot gave Kai'Sa two minor but significant nerfs- increasing the cost of Supercharge to 4 so it couldn't be cast with spell mana alone on the turn Kai'Sa hit the board, and changing Second Skin from a Focus-speed spell to a Slow spell, not only causing Kai'Sa decks to lose some tempo, but also allowing it to be disrupted by removal spells targeted on the fragile keyword-holders (such as the 1-HP Valor) Kai'Sa was attempting to copy keywords from. However, as with Bard, the deck still remained prevalent in the meta afterwards.
• Jax's Weaponmaster followers are intended as Weak, but Skilled units that make up for their low stats with their Improvised Equipment, allowing them some versatility and synergy with Equipment-based cards. What people quickly realized, however, was that Concurrent Timelines allowed you to transform the weak-statted Weaponmasters into much bigger units while still keeping the Improvised gear, allowing them to ruthlessly out-tempo opponents with huge bodies on board. This got Concurrent Timelines bumped up from 1 mana to 2, making Timelines more of a tempo loss to cast in an effort to rein the strategy in (and notably putting it in range of the 2-cost Nopeify!).
• Noxus/Bilgewater Pirate Aggro has had its showings in the top tier for its ability to shred the enemy's Nexus with big boards in record time, until it was eventually reined in by Crackshot Corsair being nerfed into oblivion and Gangplank getting a slap on the wrist of his own. Then came Illaoi's Spawn package and, in particular, Riptide Sermon, which previously dealt 4 to a unit, Spawned 3, and burned the enemy Nexus for 2. All three parts of the spell were amazing for aggro decks (and, for that matter, nearly every Bilgewater deck): the burn is obviously nice for a deck that wants the enemy dead ASAP, but the real meat is the sheer tempo swing of potentially killing a mid-sized blocker and dumping a 3/3 on board, which more often than not resulted in the opponent taking crippling damage or being finished off on the spot. And if that wasn't enough, the package also included Eye of Nagakabouros, an amazing draw card that also puts a 2/2 on the board at Burst speed, allowing Pirates to refuel and then immediately swing with an extra body on board. To address this powerhouse of a deck, Riot elected to lower both of Sermon's damage numbers by 1 while axing Decimate to 6 mana, weakening the deck's finishers and making Sermon itself less of an auto-include. Meanwhile, Eye of Nagakabouros continued to be an absurdly versatile card and was eventually nerfed from Burst to Focus speed, removing its ability to put bodies on board during combat.
• While Kai'sa was the most notable mono-champion Shurima deck, Viego also staked a claim in the territory. What Riot hadn't fully expected was just how good Shurima was at fetching and protecting champions, and Viego took full advantage of it to become a powerful, snowballing threat; like Kai'sa, having Viego as the only champion meant a guaranteed fetch with Rite of Calling, Ancient Hourglass proved to be a superb protective card by flickering your Champion out of existence for a turn to dodge spells (with the added benefit of being usable with Camavoran Soldier to proactively generate threats), Rite of Negation essentially functioned as a Shuriman Deny, and the buffed Quicksand proved to be an incredible combat trick. Between Viego and Kai'sa (both of whom ran basically the same defensive package), Riot eventually had to hand out a liberal number of nerfs, with Ancient Hourglass bumped up from 2 to 3 mana, Rite of Calling getting a cutting nerf from 0 mana to 1, Quicksand only reducing -1 Power if used on two targets, and Viego himself getting raised from 5 mana to a more uncomfortable 6.
• After a lengthy stint of being an underperforming Champion, Swain was thrown a massive bone in Patch 3.16, getting a huge buff of +1 Power in both forms and, much more significantly, Overwhelm at Level 2. The community immediately reacted with dread at the change: not only is Overwhelm powerful in its own right, Overwhelm damage to the enemy Nexus triggers Nexus Strike effects, and Swain's Nexus Strike is an absurd 3 to the enemy Nexus and all enemy units. Because Swain can level up surprisingly easily in hand or deck (especially with Watchful Idol in Bilgewater builds, which provides up to half his level up condition by itself), dropping him on curve nets you an overstatted beater that must be blocked with something that has at least 3/5 in stats due to his keywords, meaning a turn 5 or 6 Swain all but forces the opponent to trade off their strongest unit to avoid having their board ripped to shreds, and that's before Swain's other ability to stun enemies when you deal non-combat damage to the enemy Nexus makes him even harder to stop. Swain's reign of terror lasted a bit over a month before his Power buff was repealed. That still didn't quite keep him in check because of how ridiculously easy he was to level up, leading to his level up condition being increased from 12 to 16 damage in Patch 4.8 so he couldn't be played on-curve every game and proceed to wreck house. It took a couple more patches before they pinpointed Watchful Idol and Swain as being a problematic combo, at which point the Idol's health was nerfed from 5 to 4, meaning it can only trigger its effect twice instead of thrice (thus contributing only 4 damage to Swain's level up instead of 6) and allowing Swain's nerf to be loosened, bumping his damage requirement down from 16 to 14.
• "Domination" brought to the table two Champions which proceeded to, well, dominate the meta: Seraphine and Vayne, to the point where for a time, you'd be hard pressed to find a Piltover and Zaun deck without the former or a Demacia deck without the latter, and both were nerfed in under a month:
  • Seraphine is essentially a mini-Karma with a much easier level up condition, allowing your new spells with a cost of 2 or less to double cast once she's at level 2. In addition to providing insane value on her own since she only needs you to play 6 different spells to level up, Seraphine also came with a support package of Drum Solo (a draw 2 that almost refunds its own mana cost if you trigger Flow, which isn't difficult at all in a deck built around her), Fanclub President (which Manifests a new 5-cost spell and discounts it by 3, which not only gives huge value but also either levels Seraphine or makes her able to duplicate it) which saw play almost everywhere because of how trivial the conditions are, and that's before taking into account her ability to straight-up OTK the opponent if she and Ezreal are allowed to exist on the board at the same time. A vast majority of top decks ran Seraphine because the random card generation both granted absurd amounts of value and made it nearly impossible for the opponent to play around your cards, since the generated cards were usually not even in your regions. In an attempt to keep her package in check, Seraphine's level up was swiftly nerfed to require a much more demanding 9 new spells, while Fanclub President was nerfed to 5 mana.
  • Vayne generates a Tumble in your hand every round or reduces its cost if you already have one. Showing that Riot still hasn't fully learned the power of spammable free attacks, Vayne enables incredible synergies with pretty much every Champion that likes to attack... of which there are simply too many to count. Being able to cheat out an equipment for cheap is icing on the cake as well, especially when Weaponmasters are brought into the mix with the potential of generating Upcycled Rake to give Scout to anything you want, turning Tumble into a makeshift Rally on top of everything else. Tumble was duly bumped up from 3 mana to 4, meaning Vayne can no longer enable huge swing turns using just spell mana unless you keep Tumble in hand for at least one full turn.

Glory in Navori

• Out of all the cards in the game's history, you'd be hard-pressed to find one more despised than Sump Monument. This was a 3-mana Piltover and Zaun Landmark that negates all damage done to your Nexus (except by Puffcaps) and instead shuffles 4 Puffcaps into your deck for each point of damage prevented. Because Puffcaps can be spread pretty thin in a deck, this made players almost unkillable; even if your opponent swung with enough units to kill you several times over, you'd nullify it and just take a handful of damage from Puffcaps on your next draw instead, and since Piltover and Zaun was a region with a generous amount of burn, you could often kill your opponent on the crackback or over the extra turns that Sump Monument bought you. For even more fun, Starlit Epiphany allowed you to simply replace your entire deck with a bunch of copies of Behold the Infinite, instantly flushing out all the Puffcaps and letting you outvalue your opponent with overpowered Celestial units. Even after being nerfed to 4 mana and planting 5 Puffcaps per damage prevented, Sump Monument is often still a win condition against decks without Landmark removal.

Fate's Voyage

• Chemtech Drake had a brief stint of brokenness before being hotfixed due to an oversight with its effect. The Drake is an 8-mana 8/6 Piltover and Zaun follower that allows you to draw a card each time you played a spell, and each time you draw while your hand is full, it deals 1 damage to the enemy Nexus. The problems arose when you paired it with Loaded Dice, which causes you to Nab a card every time you damage the enemy Nexus on the round after it was played. Nabbing cards counts as drawing. You should be able to see where this is going. The Loaded Dice + Chemtech Drake interaction was quickly patched out of the game, partly because milling your opponent's entire deck and burning all of their health in 1 turn was patently ridiculous and partly because it literally broke the game, often causing crashes when it went off.
• Wildfire was a 1-mana Noxus Slow spell that deals 1 damage to the enemy Nexus, plus 1 for each Wildfire you previously played, and then shuffles a copy of itself into your deck. Before release, it didn't exactly set the world on fire; after all, the baseline was a worse Warning Shot and you had to actually draw the new copies to get anything more than that. Turns out that second part was a lot easier than expected - Ionia had a lot of ways to draw spells, so Wildfire saw play in aggressive Noxus/Ionia decks where your only spells were Wildfire and Rejuvenating Breeze while the rest of the deck would be filled out with tutors like Rivershaper and aggressive units to pressure the enemy Nexus. This allowed Wildfire to be re-drawn easily and ramp out of control very quickly, to the point where even healing and Lifesteal would often not be enough to prevent a one-turn-kill. As such, Wildfire was nerfed to 2 mana to make it harder to chain multiple of them in a single round.
• Heisho, Shell of the World was released as a 9-mana 9/9 Ionia follower with Spellshield that made your first card each round cost 9 less. This included the first card you played after it in the same round, basically making it a free 9/9 with Spellshield that paid for itself every round. This card's impact on the game was immediately and keenly felt, given that it was by far one of the most powerful mana-cheating effects in a game that had previously been generally cautious about making them. Naturally this meant Heisho had to be killed as quickly as humanly possible, but being such a massive pile of stats with Spellshield meant it was impossible to do that efficiently, and even if you managed, your opponent could simply throw out the biggest thing they could play in response... except not really, because due to a bug, Heisho's discount would still be usable for the round even after Heisho itself was removed. It absolutely wrecked house in decks built around Volibear and Elder Dragon in particular, since Volibear's package ran cards that could generate Sigil of the Storm which in turn could discount Heisho itself, allowing it to come down on round 6 or 7 and then be followed up by something exceptionally nasty like Buried in Ice or Volibear himself. It took a scant three days before Heisho was hotfixed, removing the Spellshield and nerfing it to 10 mana while fixing the bug that caused Heisho's discount effect to linger after death.

Lab of Legends/Path of Champions

• With the ability to draft passive powers and items to buff your deck, Lab of Legends - and its successor, Path of Champions - has some amazingly overpowered combos, mostly kept in check by the randomness element (for example, a deck with Bouncing Blades or Feral Senses that gets a useful effect, such as healing, on the card it mass-produces will be able to trigger it every turn - especially with Feral Senses, since that doesn't even cost mana), but some powers get very silly with the right deck. For example, Ekko levels up very easily with Feral Senses, while a deck like Shyvana or Pyke where a lot of followers have multiple keywords gets huge bonuses from Evolution (particularly Pyke, who has a 1-drop with two keywords, and Pyke himself also has two keywords and becomes monumentally easier to level up). In general, you need to be able to put together an OP combo like this to be able to win, largely because of the Guard Bots...
• Yipp's Genius, a power that gives 1-cost units +2/+2 when summoned, has outstanding synergy with heroes that have easy access to them. The massive stat buff often allows your early-game units to trade far more efficiently than their cost would suggest. Unsurprisingly, Irelia and Azir are easily two of the best candidates for using the power, given their ability to continuously summon disposable 1-cost attackers that the power buffs from a piddly 1/1 to a hefty 3/3.
• Certain support champions become far stronger in this mode than they do in constructed play, given the ability to stack items on them to beef them up. A stacked Renekton or Zed, for instance, can single-handedly shred most opponents, Renekton by leveling up quickly and dealing monstrous Overwhelm damage and Zed by swarming the opponent with high-power Living Shadows.
• By far the most infamous item + card combination is Katarina with an Archangel's Staff (Mana Deposit in Path of Champions). When leveled up, Katarina Rallies when played and returns to your hand after she strikes, and with Quick Attack, this means that an attacking Katarina retreats before her blocker has a chance to damage her. This is normally balanced out by her 4-mana cost... which gets refunded by Archangel's Staff if she has one, meaning that this combination forms a nearly-unstoppable one-turn-kill against everything as Katarina can just keep poking the opponent with her infinite Rallies until they die.
• Vault Breaker with Chalice of Harmony (or any other combination of items that reduces its mana cost to 0) allows you to spam it as much as you want as the Fleeting copies will also cost 0, meaning that any single unblocked unit now has the potential to instantly end the game. It's technically kept in check by an in-game safeguard against infinite loops that only lets you cast Vault Breaker 15 times, but given that this still amounts to 30 extra damage, it's still incredibly lethal.
• Jinx is the starter champion you get for Path of Champions, and to call her a Disc-One Nuke would be an understatement:
  • Unlike other champions, Jinx's starting deck gets access to overpowered, uncollectible cards from the get-go (while it is possible to acquire otherwise uncollectible cards in your deck under other circumstances, those usually have to be somehow drafted). Rocketboarder, a 2-mana 3/3 with Quick Attack is very neat on its own for the outrageous aggressive statline, but the real treat is Pow-Pow, a 2-mana spell that deals 3 to a unit at Burst speed. Access to uninterruptible removal is an absolute life-saver against tougher enemies, and as the cherry on top, leveling Jinx up reduces its mana cost to 1.
  • Her 1-star Power, which is given to you for essentially free to show off the mechanic, deals 1 damage to the enemy Nexus any time you play or discard a card. Yup, just playing the game normally is enough to exponentially accelerate her game plan, making Jinx the undisputed queen of Path of Champions aggro while synergizing amazingly with support Champions like Gangplank and especially Swain (who not only levels up without effort but also handily mass-stuns the opponent's board whenever you do anything) as well as every Plunder effect under the sun. And as if that wasn't enough, leveling her to 3 stars upgrades the power to also deal 1 to a random enemy unit each time it triggers, sweeping away weaker units just by playing cards.
  • The Relic system allows you to equip a Relic to a champion to give them bonus effects at the start of a run, and Jinx naturally has an incredible synergy with one: The Loose Cannon's Payload. When the equipped Champion is played, this relic discards your whole hand and replaces it with that many copies of Pow-Pow. The synergy with the rest of Jinx's kit should be evident given what has already been stated, but to sum it up: equipping Jinx with this means that when you play her, she levels up instantly, burns the opponent for the number of cards in your hand (and shreds open the enemy's board if you're at 3 stars), fills your hand with Burst-speed removal that costs 1 mana a pop (and also burns the enemy Nexus when played), and if you have her 2-star power, you get a free Super Mega Death Rocket! for leveling her up for even more burn and board-clear. If you don't kill the opponent within the next three turns after that, something has gone horribly wrong.
• Darius's synergy with The Curator's Gatebreaker deserves special mention with regards to Champion + Relic combos. Gatebreaker causes the equipped champion to immediately strike the enemy Nexus when summoned, and Darius levels up when the enemy is at half health or less. Combined with his very aggressive deck, and what you get is either Darius immediately smacking the opponent hard enough to level up and then potentially having a regular attack to use for good measure, or if the enemy is already low, a level 2 Darius can kill the opponent on the spot. And then you start equipping items on Darius or pairing him with powers like Stabilize (summons an exact Ephemeral copy of Champions you summon), at which point things get really crazy.
• Pick Teemo. Give him Galeforce^note Grants Scout, but recalls your champion at round end and two Curator's Galebreakers^note The champion strikes the enemy's nexus when summoned. A level 2 Teemo doubles the number of puffcap mushrooms in the enemy's deck whenever he strikes the nexus, which means that, with this setup, he will double the amount of mushrooms four times (two from the Galebreakers, plus two attacks with scout), or only two if you don't have the attack token. The recall effect ends up being more helpful than inconveninent since Teemo only costs one mana to summon, and it allows you to constantly summon him every round to trigger the Galebreakers again and again. As expected, this will fill your opponent's deck with an unimaginable amount of puffcaps in a very short time, practically guaranteeing that they'll pull dozens (if not hundreds) of puffcaps at round start and lose the game in a few turns. Getting additional powers like Rally, Stabilize or anything else that allows you to plant more puffcaps will only make this even faster.
  • No longer the case as of patch 4.8. Curator's Galebreaker now has a -1/0 penalty, making Teemo unable to strike the nexus unless he has leveled up or is buffed by another relic. Galeforce now also shuffles your champion into your deck instead of putting them back in your hand, making the strategy of continuously summoning Teemo a lot harder.

---