The Big Bad is sending our hero (and his Ragtag Bunch of Misfits companions) through the wringer. He clearly has the power to wipe them out any time he feels like it. But he's content (for now) with sending out wave after wave of progressively stronger mooks, Elite Mooks, and the occasional Quirky Miniboss Squad to test our hero. Maybe he's even fought them personally, but let them live, maybe even let them think they beat him. Maybe he even leaves them alone to train for their inevitable confrontation. So why don't they finish the hero off and be done with it?
Because it's Part of The Plan. Maybe he needs the heroes strong enough to get to the top of Mount Tropey and retrieve the Crown of Trope-Tan. Maybe he needs The Chosen One as strong as possible before he takes his power or body as his own. So he keeps sending out one stronger opponent after another to test Our Hero (or lets him seek them out on his own). After all, if he can't handle that, he's no good for the Master Plan. It's also possible that the Big Bad just may be a Blood Knight who wants to beat him at his strongest, or its no fun.
The pitfalls of such a plan, however, are painfully obvious. If the schemer needs his pawn to secure the Crown of Trope-Tan due to restrictions on his own presence, he needs to make certain the pawn will deliver it to him straight away, lest the pawn put it in safekeeping, destroy it or, worse, use it against him. There are many ways to go about ensuring it, however - a hostage exchange is one such way.
If the schemer is seeking the hero's body or power, there is a fine threshold between "strong enough to work" and "too strong to handle" that the schemer needs to keep in mind at all times - the instant the threshold is crossed, things get complicated. A Blood Knight is less inclined to care, especially if defeat is the desired result. They may also forget to keep up with the heroes, themselves.
Both of these also share the same pitfall as all Evil Plans—the plan is only good as long as the pawns never figure it out. The instant they do, they may try to incorporate a power incompatible with the schemer or seek to invoke a backfire. Long story short, if they catch on, it's only a matter of time before the schemer and his plan go to hell.
This is a subtrope of Evil Plan and Just Toying with Them. See also: I Let You Win, Not Worth Killing, Bring Him to Me. Often a part of a MacGuffin Delivery Service if the hero is an Unwitting Pawn. Compare Stealth Mentor. Contrast You Will Be Spared.
- Cell and Vegeta on Dragon Ball Z took turns with the Blood Knight variant of this trope. Vegeta could've easily destroyed Imperfect Cell (or let Future Trunks do it). But Cell appealed to his Saiyan blood, allowing him the opportunity to absorb Android 18 and achieve full power. Likewise, Perfect Cell could've wiped the Z-Warriors out after this. But his Saiyan blood (since he was created using the DNA of the most powerful warriors, including Goku and Vegeta) caused him to give Goku and company time to train and get stronger, so he could crush them at their best, with the whole world watching. Cell then falls into this trap a third time by intentionally provoking Gohan into Super Saiyan 2 during the Cell Games, who proves to be his downfall.
- In Naruto, Itachi decides not to kill Sasuke along with the rest of the Uchiha clan. The reason why he does this changes several times, always somehow related to this. Then it's revealed that he was Good All Along and wanted Sasuke to kill him for his actions.
- Saiyuki: Journey to West: The Sanzo party travels over land at the request of the Merciful Goddess, in order to be more of a team.
- In Bleach, Aizen allows Ichigo to go through one last bout of Training from Hell because he wants him to be stronger when Aizen finally "eats" him. Given how Drunk with Power Aizen is during their later fight, it becomes clear that Aizen just wanted a Worthy Opponent to crush with his new powers. It backfires on him because Ichigo took too many levels of Badass and was actually much stronger than Aizen anticipated.
- In Lost Universe, the main villain Yami doesn't kill Kain Blueriver when they first meet, wanting him to be stronger before corrupting him. Making him stronger worked too well.
- In Fullmetal Alchemist, this is why Edward Elric and Roy Mustang survive long enough to win, in the manga. Well, Roy at least; Ed is already 'strong enough;' it's just that it's not yet time for the sacrifice.
- In Hunter × Hunter, Hisoka is the Blood Knight variant. He just wants to have fun and fight strong opponents, and Gon and Killua look like they could grow up really fun to fight, so he lets them live and encourages their development. If they don't have potential, he just straight up kills them.
- This is the guy who cut off his own arm to make a casual fight more interesting. He had a years-long plan that involved betraying some of the most dangerous people on earth just to fight their leader. You should have seen his face when a side-effect of relying on Kurapika's vendetta turned out to be that Chrollo Lucifer would die if he used his powers again. Chrollo thought it was pretty funny, himself.
- In One Piece, Mihawk spares Zoro's life in their first encounter even though he's a massively inferior fighter. This is because he sees Zoro as having the potential to give him a truly challenging fight once he's traveled the Grand Line. He even goes so far as to personally train Zoro during the timeskip.
- In Shaman King, Yoh tells Hao that he's not afraid of him, because Hao will only kill him once he's reached his full potential.
- In MÄR, Phantom sees the potential in Ginta and actively encourages him to get stronger. Even preventing his army from killing him during their invasion of Dorothy's hometown. Of course this came to bite him in the ass during the final round of the War Game between Ginta and him as Ginta begins overwhelming him, to which he even lampshades before pulling out his trump card which likewise fails.
- In Revolutionary Girl Utena the dueling game is designed with the purpose of strengthening the champion's Soul Sword to be stronger and to encourage them to exhibit princely virtues. It is strongly implied that Utena's many miraculous wins were actually due to Anthy and Akio's intervention as they planned for Utena to reach the final duel, at which point Akio could take her sword from her and use it to try to regain Dios's power, as he has done multiple times before with previous champions.
- In Kill la Kill, Satsuki makes Ryuko duel the club leaders, the Elite Four, and Satsuki herself to strengthen Ryuko so that she can help fight Satsuki's mother, Kiryuin Ragyou, when Satsuki makes her planned HeelFace Turn.
- In A Certain Magical Index, Aleister Crowley manipulates things behind the scenes so that Touma Kamijou constantly runs into bad guys and problems to fight and solve, wanting him to gain experience and get stronger for some undisclosed goal. Later, the True GREMLIN organization reveals that Touma's entire adventure with Othinus was an "experiment" of their design to manipulate Touma's growth.
- In Yu-Gi-Oh! 5D's, the Yliaster trio sends trials and opponents the heroes' way like the Ghost Robots and the Fake Jack Atlas. This is to force them to improve and grow stronger, so that they release more energy when they duel, which helps their plans.
- Freya from Is It Wrong to Try to Pick Up Girls in a Dungeon? is a weird case in that making Bell stronger is the endgame. She really enjoys watching him fight.
- In Campione!, Athena wants Godou Kusanagi to master his powers and become stronger, so that it will be more epic and satisfying when they finally have a rematch.
- In "The Lord of Calamity" from Tales of Zestiria The X, the Lord of Calamity, Heidalf, states that he shall let Sorey grow in his powers as a Shepherd until he becomes a shining light to the people of the world, only to then rip it from them.
- My Little Pony: Friendship is Magic (IDW): The trials Chrysalis puts the Mane Six through are meant to strengthen their friendship so their emotions will peak and Twilight will be at her strongest when she drains her magic.
- This winds up backfiring as Twilight's magic turns out to be much stronger then she realizes. Added with the magic comet amplifying her power and Twilight manages to defeat Chrysalis in a one on one duel.
- This is pretty much Phobos' plan in the first story arc of W.I.T.C.H., as he wants Elyon's power to peak before draining it. Being an Evil Genius, he takes a novel approach and has Cedric, who got the nickname of "Prince of Lies" for a reason, trick her into joining his side so Cedric can teach her and make her strong enough to handle wearing the Crown of Light, that will make her power peak... And, thanks to Phobos' enchantment, instantly drain it and leave her on the verge of death.
- In Harry Potter and the Natural 20, Voldemort continuously sends minions and dangers Milo's way. Milo levels up with each fight and adventure and will eventually gain the power to revive the dead, a skill of course useful to the Dark Lord's plans.
- We see a form of this in Harry Potter and the Goblet of Fire where "Mad-Eye Moody" nudges and helps Harry along in his Tri-Wizard Tournament challenges, for the sole purpose of luring him into a death trap If he isn't good enough to reach the Triwizard Cup, then he won't reach the cup.
- In The Pendragon Adventure, This trope is the reason Saint Dane doesn't simply kill all the Travelers. In fact, it's also the reason he even lets Bobby find him in any territory at all. When Saint Dane says he's done with his work in a territory, he means it.
- In Artemis Fowl: The Opal Deception, Opal waits a year before having herself revived from her self-induced coma. This is partly because she wanted to throw off suspicion. It's also, though, because she wanted to wait until Artemis, Butler, Holly, Commander Root and Foaly were all back at the top of their game before unleashing her new plan so that victory would be that much sweeter.
- In Knight Life, after Morgan Le Fey's (Morgana's) latest plan to destroy the mayoral ambitions of Arthur Penn (Pendragon) fails, she decides that if he thinks things are going great now, then it couldn't help to build up his hopes even further. She'll make it seem like things are going well with the election, only to crush his dreams at the last minute.
Morgan: All right, fine. You want to build up your hopes, Arthur? Fine. I'll build them up even higher, then, and that way they'll make an even louder crash when they fall! And nothing will distract me from my purpose! Nothing!Lance: Morgan? Will you spank me?
- In the updated Battlestar Galactica, it's never exactly clear why the Cylons didn't simply Zerg Rush the fleet, destroying Galactica and picking off the rest of the fleet at leisure. After all, they'd wiped out 99% of humanity already. Why tiptoe around killing the rest? It's been suggested (but never spelled out on-screen) that this was Cavil/One's doing: He wanted to prove to the Final Five that Humans Are Bastards and not worth saving (thus justifying his own hatred of the Five and humans) by hounding what was left of the Colonies until they turned on each other (which sort of was the case). The hypocrisy of this did not go unremarked upon.
- In Kaizoku Sentai Gokaiger episode 28, the Monster of the Week is an alien bounty hunter and thrill-seeker who does it twice. In the past, he nearly killed Captain Marvelous but stopped short and even injured himself to create a weak point and taunted Marvelous to come back strong enough to challenge him. Then in the present, he handily defeats Marvelous a second time (mostly due to his being paralyzed by fear) and leaves mid-fight despite being paid to kill the Gokaigers.
- In the Supernatural episode "All Hell Breaks Loose, Part One" (S02, Ep21), the Yellow-Eyed Demon reveals that he has been working to make Sam stronger as part of his Evil Plan.
- The Flash (2014):
- Reverse-Flash wants Flash to master his speed powers, so that he can force Flash to travel through time and return him to his home in the future.
- Likewise with Zoom, who spends the first part of the second season sending out supervillains for the Flash to practice on, though in his case he wants to kill Barry and take his speed.
- The reason a father would name his boy Sue.
- In Dragon Ball Fighter Z, Big Bad Android 21 has the power to turn people in sweets, but she wants the fighters she faces to be as strong as possible, since stronger fighters taste better to her. Too bad for 21 that Goku and company get stronger than she can handle, and she's wiped out in all three story arcs by her own gluttony getting the better of her.
- In Final Fantasy IV, Golbez can't get into the Sealed Cave himself. Cecil can, but isn't strong enough to get through the deathtraps on his own. Cue the Sorting Algorithm of Evil.
- And in Final Fantasy XIII, this is indicated to have been in effect for the first portion of the game. Someone rather high up wants the Pulse l'Cie to get stronger. Turns out it's Primarch Dysley, a.k.a. the fal'Cie Barthandelus, as part of his Thanatos Gambit. He can't kill himself or even go easy on the Pulse I'Cie so they have to be strong enough to sincerely kill him.
- Happens again in Final Fantasy XV. The main villain Chancellor Ardyn Izunia arranges the supposed political marriage between Noctis and Lunafreya which conveniently sends him on a roadtrip away from the false peace treaty (which the villain also arranged) between Niflheim and Lucis. So while Lucis falls, Noctis is safe. The villain later briefly joins the heroes on their trip without revealing himself to help get them started on the quest to unlock Noctis' full power. In the end, as Noctis is absorbed by the Crystal, Ardyn reveals his motives. Turns out he's an immortal member of Noctis' bloodline who wants revenge on the Astrals and their "chosen" for being rejected after he had tainted himself absorbing countless daemons in his quest to heal people of the Starscourge. While he could have killed Noctis at any time, doing so would have brought him no satisfaction. Ardyn wants Noctis to become the "King of Light" because that will make killing him even sweeter.
- In Golden Sun (both games), Alex does jack squat to help his allies defeat you, as part of a plan to unleash Alchemy on the world. 30 years later, he's STILL at it.
- This is the Lich King's plan for the World of Warcraft expansion that bears his name. Allow the player characters to grow stronger and better geared, lure them into Icecrown Citadel, then slaughter them all and turn them into the elite vanguard of his undead armies. It almost worked, except for the fact that after the slaughter part he took a little too long to gloat...
- Also sometimes presented as the justification for opening the Dark Portal and allowing the Horde to invade, beginning the events of the original Warcraft: Without years of battle-hardening every race on Azeroth, they never would have been prepared to resist the Burning Legion.
- In Super Paper Mario Dimentio interferes with the protagonists for this purpose, allowing them to defeat Count Bleck, thus freeing the Chaos Heart for him to use.
- In the first Super Robot Wars Original Generation, every villainous organization is like this. In the cases of both the Divine Crusaders and Ingram Prisken, it's obvious that they're Stealth Mentors. The Aerogaters, on the other hand, want the heroes to be as strong as possible for when they're Brainwashed and Crazy.
- Played twice in Kingdom Hearts: Birth by Sleep. Master Xehanort encourages Terra to train and strengthen his powers in preparation for stealing his body to cheat death, while Vanitas encourages Ven to become stronger because their powers need to be equal to complete the χ-blade.
- Diablo I. Whether it was Diablo's plan or not, it works. Failure Is the Only Option, and that's why he's 10 times stronger in Diablo II.
- Blue Dragon. Those Living Shadows you use to fight? They're fragments of Nene's one. He didn't feel like doing his own Level Grinding, so he let you do it for him. He promptly takes the Shadows back when you confront him at the end of Disc 2, revitalising himself and leaving you powerless.
- Akuma from Street Fighter seems to imply that he views Ryu in this light. He could easily destroy Ryu but instead lets him live and train, believing that with proper nudging, he will develop the same dark fighting spirit that Akuma embraces. In the UDON Comics series of Street Fighter comics, this is outright stated after Akuma wipes the floor with Ryu and lets him live, leaving him with the trope as his parting words. In the end, this is subverted as Ryu chooses to reject the Dark Hadou and walk a more pure path as a warrior.
- inFAMOUS. Kessler could easily have killed Cole any time he liked, if he wanted Cole dead. He doesn't do this, however because he's actually a much older version of Cole from a Bad Future, who's traveled back in time to ensure that Cole gets strong and ruthless enough to beat the opponent Kessler couldn't, and so prevent it from becoming a Bad Future. Kessler shows no such qualms about killing Cole's loved ones, however.
- The God King from Infinity Blade subverts this. He never hesitates to impale defeated warriors and absorb their strength with the Infinity Blade. However, he never tries to nip things in the bud by hunting down the warrior's son when he's still a child because he wants a worthy champion to help him fight the other Deathless.
- Castlevania: Curse of Darkness starts out with Isaac luring Hector to his castle, enticing him to gain back his lost powers by getting his lover Rosaly killed and waiting for revenge. Isaac could easily wipe the floor with Hector right there in front of the castle, but he would rather see Hector corrupt himself again with devil powers and become a Worthy Opponent so that killing him in the end will be more delightful.
- Castlevania: Lords of Shadow has the main Big Bad bide his time and watch Gabriel slaughter his brother and sister, because he has one hell of a plan: Zobek needed Gabriel to become strong enough to kill two Lords of Shadow and survive until reaching the heart of his realm, but the initial problem was that Gabriel might have kicked his ass afterward. After mind-controling Gabriel (again) into killing his friends and taking an Artifact of Doom with a self-destruct mechanism that only Zobek could activate, he let Gabriel reach his full potential and just activated the artifact to off him. And then he got upstaged when it turned out that neither one was strong enough to overcome Satan.
- If one looks at the plot fragments of BlazBlue in detail, it becomes clear that Relius' plans for Makoto essentially boil down to this trope. The Nox Nyctores Houyoku: Rettenjou incorporates the anti-seithr module known as Kushinada's Device to interfere with the operation of ars magus - that includes not only armagus weapons and other Nox Nyctores, but also the ars magus technology on which the world now runs on. While Rettenjou was left fully powered after the Dark War due to Nine not getting around to sealing it (blame Terumi), Relius finds its current soul to be inadequate, and rather than smelt an entire NOL branch like Terumi did to temper Noel into Mu-12, he would rather fortify a soul to its breaking point before throwing it into Rettenjou and invoking the Day of Destruction. Given how hardy and powerful it is, the soul of Makoto Nanaya is his chosen warhead. The risk and reward are equally immense here - even if she can't become powerful enough to topple Relius, a quote by Terumi about Relius' interest in Makoto to Makoto herself is a good place to start investigating this plan, and if she pieces it all together, Terumi won't be the only one whose schemes she sends belly-up.
- XCOM: Enemy Unknown: The alien invasion is essentially a Training from Hell, intended to develop humans into a force strong enough to fight some unspecified foe on behalf of the Ethereals.
- Dot Hack GU: It comes to light in the second volume that Ovan is in control of AIDA, and has been sending trials at Haseo all this time to make him stronger. The reason? He is host to the murderous AIDA known as Tri-Edge. His powers as Corbenik the Rebirth would allow him to "reset" everything and wipe out AIDA if he dies, but He Cannot Self Terminate. Thus, he acts the part of the villain so that Haseo will kill him.
Become stronger, Haseo. Strong enough to kill me.
- This is Erim's plan in Lufia: The Legend Returns: train a group of heroes strong enough to defeat the Sinistrals, including herself, in order to end the cycle of their resurrection.
- In Fire Emblem: Path of Radiance, The Black Knight Zelgius wishes to surpass his master, the legendary swordsman Gawain. The only problem with this is that "Gawain" is now Greil, who crippled his own sword hand after being consumed by a powerful chaotic magic in order to protect everyone from what had happened, The Black Knight killed his mentor, but felt empty doing so against such a husk of a man and spends the next two games preparing for a big fight with Ike, Greil's successor.
- In Dies Irae, a big reason to why Reinhard constantly leaves the main hero Ren alone is cause he wants him to reach the absolute height of his power. Main reason for this is that Reinhard have always been so unreasonably powerful that nothing in the world has ever given him a challenge or allowed him to experience defeat. Win or Lose, at the end of the day, he just wants to feel fulfilled.
- In The Wotch, it's clear that Xaos has enough power to take out Anne or Miranda (possibly both of them at once), as does Kohaine. He's explicitly testing Anne, wanting her to grow as strong as possible before stepping in and stealing her powers. Why he can't just take them now and be done with it...? It's revealed during the Hunting the Most Dangerous Game arc: Anne has Reality Warper powers capable of ripping apart dimensional boarders. However, it's incomplete.
- In The Order of the Stick, Xykon invokes this trope to Roy, offering to let him go so he could gain a few levels because "good heroes make good villains." Roy decides to fight him anyway. (Xykon then subverts the trope by going ahead and killing Roy. Don't worry: He gets brought back.)
- Later, General Tarquin does it too, letting Elan go even after he's tried to kill him. so he can gain some more levels, finish the current questline, and THEN come back to try again. His reasons are cleverer than most, however - he basically says that, should he lose in a climactic duel against a powerful hero, he'll go down in history as a legendary villain. And if he wins? Then he wins. Of course, the fact that he's Elan's father may also play a role in his decision because father-son feuds will make his legend even better!
- In Our Little Adventure, the Palm Tree Ghost tells Julie that the city of Everwood should be her next destination, but she'd probably want to spend some time gaming a level or three before proceeding there. Made explicit later, when they discover that the second Magicant piece was far closer to their original starting point than the first They're told that although that piece was closer, the monsters in that area were far stronger, and they would have been slaughtered had they tried for the closer one first.
- A variant on this shows up in 8-Bit Theater, when Sarda reveals that the true purpose of the Light Warriors' questing was to make them as strong as possible, just so they would know that not even that much strength could stop him from killing them.