This is when members of the main cast can all get more powerful, but their power relative to each other never changes.
If the main hero starts out with roughly the same strength as the main villain, the two of them will always be at the same strength. If one of them gets an upgrade or Takes A Level In Badass, the other will soon follow. Likewise, if the hero's sidekick is roughly half as strong as the hero himself, then he will always be half as strong. He will never surpass the main hero, because that would upset the narrative dynamic.
This trope was originally titled Distribution of Ninjitsu, because of its relation to other Ninjitsu-themed trope names. For example, a given group of Ninjas is subject to Conservation of Ninjutsu, so the more there are the weaker each is. Groups are likewise subject to Conservation of Competence, if one person is very competent their supporters will be very incompetent, and vice-versa.
Sometimes, both of these combine in the form of Fixed Relative Strength. When a group, cast, or faction is subject to Fixed Relative Strength, the total amount of fighting ability is more or less constant but unevenly distributed, establishing a ranking of who's stronger than who. These ranks tend to stay constant even after characters get stronger. Why is this done? To avoid having everyone be so awesomely powerful no one stands out. It's much like limiting a character type or trait to avoid over saturating the setting.
This can be distributed a few ways. Usually, much like Authority Equals Asskicking, the leader of the group will be the strongest, and all down the chain of command the Ninjutsu gets smaller and smaller until ground level Mooks or Red Shirts are pushovers. If the group is evil, this is much like an in-season Sorting Algorithm of Evil and Sliding Scale of Villain Threat.
Heroes will usually have an analogous ranking to the villains, so each member of the The Psycho Rangers will be as badass in their own group as their respective opposite in the Five-Man Band. However, since the heroes tend to be just five, and tend to have no mooks, they will concentrate their combined Ninjutsu such that they are usually slightly stronger than their opposite. This is usually not the case with The Hero and The Lancer when they face the Evil Overlord and The Dragon, as they tend to "hoard" some ninjutsu from their underlings to make them stronger than their analogue.
Another possibility is that the Five-Man Band may sometimes have a near equal distribution of Ninjutsu among its members, with the leader being a well balanced Jack-of-All-Stats while the rest have a specialty. This explains why the Monster of the Week usually has more raw oomph than any 2 or 3 heroes, but falls when they make a Combined Energy Attack or use The Power of Friendship, or form a giant robot. It's also worth noting that each side does not necessarily have the same total Ninjutsu to distribute, no one said fiction was fair after all.
In the rare case the leader of the heroes/baddies is the weakest of the bunch, everyone else will be massively more powerful, like a huge bubble becoming lots of medium sized ones. These leaders often compensate this by being The Hero with What Kind of Lame Power Is Heart, Anyway?, which sidesteps Conservation of Ninjutsu.
Compare Can't Catch Up and Character Tiers, which is a video game trope where certain characters are always inherently more effective thanks to their combination of abilities and attributes than others.
- Dragon Ball Z:
- Applied with increasing consistency as the series goes on, and even becomes a major plot point. Goku is the strongest, followed by Vegeta, then Gohan, Piccolo and the other half-Saiyan children, and lastly the human fighters, Krillin, Tenshinhan, Yamcha, Chiaotzu, and finally Videl. Vegeta's seemingly eternal role as second fiddle to Goku becomes an increasingly sore point for him as the series goes on; after his moderate HeelFace Turn, no matter how hard he trains he is never able to catch up to Goku, despite both of them becoming insanely powerful compared to everyone else. This eventually boils over into a temporary FaceHeel Turn after his indignation at still being inferior to Goku after 7 years of Training from Hell following the Cell Saga causes him to allow wizard Babidi to reawaken the evil in his heart and bring out his potential, allowing him to fight evenly with Goku.
- DBZ does subvert this trope in the later story arcs. Gohan surpasses Goku and Vegeta in power to challenge Cell and save the world only to fall behind in his training later on. However, an Upgrade Artifact granted by the Elder Kai soon re-establishes him as one of the most powerful fighters. But it doesn't help that Adult Gohan is a fairly consistent Jobber (even more than Tenshinhan, originally the strongest human around), meaning that even when he's the Ultimate Fighter that "supposedly" surpasses any Super Saiyan, he becomes weaker than Goku and Vegeta since he doesn't train to maintain his power (mostly because he hates fighting). In GT and canon movies set after Z, Goku and Vegeta naturally get even better power ups such as Super Saiyan Blue.
- This can occasionally work in rather odd ways. Goku was a little bit stronger than Piccolo for Raditz, over twice as strong for Nappa and Vegeta and then had roughly triple Piccolo's power level when it came time to fight Frieza. However, Goku then got to go Super Saiyan, which is a 50x multiplier. When it came time to fight Cell, Piccolo was now only somewhat below the Saiyans when they were Super Saiyans, even briefly passing Vegeta. So in order to maintain his relative position to Vegeta and Goku, he actually grew dozens of times stronger than they did in the same time period. Still, without that kind of huge multiplier, he's never able to catch up again.
- In One Piece the Straw Hat Pirates generally all undergo badass level-ups at around the same time every other arc or so. Despite this, Captain Luffy and Zoro are always at the top, followed closely by Sanji, and the three of them are consistently considered to be leagues above the rest of the crew.
- Word of God states that Usopp will always be the weakest member of the crew, since he's meant to be closest to a normal human. To put it in perspective, at the moment the man is able to snipe someone from several miles away, during a windstorm, with a slingshot. And yet compared to anyone else in the crew, he's just not able to catch up.
- Hunter × Hunter subverts this for three of the four main characters. Their displayed fighting strength changes (as far as we can tell) from approximately
- Killua > Kurapica = Gon > Leorio at the beginning via
- Kurapica > Killua > Gon > Leorio during the York Shin Arc and
- Killua > Gon > Kurapica > Leorio at the end of the Greed Island Arc to
- Gon > Killua > Kurapica > Leorio at the end of the Chimera Ant arc.
- Killua > Kurapica > Leorio > Gon in the 13th Hunter Chairman Election arc.
- Digimon tends to have a pretty easily broken down power scaling among the main characters through the seasons. The Hero and The Lancer are generally the ones whose partner Digimon reach one evolution level higher than the rest of the group. However, there are notable subversions and outright aversions in certain cases.
- In Digimon Adventure, Tai and Matt's Digimon are consistently the ones who are the first to reach a new evolution stage and are the only digimon to reach Mega Level among the eight Chosen children. However, before said highest evolution, their younger siblings' partner Digimon were by far the strongest and the most effective against the villains. This is because Kari and TK's Digimon were Angelic in nature and naturally effective against evil and wicked Digimon.
- The aversion comes in Digimon Savers. All four main characters reach the same level of power, even if one of them temporarily outpaces the other, said person will quickly close the gap. This is the only series where the supporting cast is able to keep up with and fight on the same level as The Hero.
- Very prominent in Green Lantern. The Green Lantern Corps has thousands of members, most of whom constitute a Red Shirt Army. It is not unusual for them to be killed en masse in battles where the main characters like Hal Jordan not only survive, but win the battle. Even though they all have essentially the same power.
- Franchise/Godzilla: The titular monster often fight on par with or dominate all other monsters, however King Ghidorah is always his superior in term of power and often require teamup with either human or monster to defeat. Even the Adaptational Badass Godzilla Earth was no match for that version of Ghidorah who was a Planet Eater Energy Being.
- Very much the case with the Empire in Star Wars, especially the original trilogy. Stormtroopers are some of the most ineffectual soldiers around, a situation that does not improve if you increase the numbers of them on the battlefield, as in Return of the Jedi where an entire legion of them are defeated by a bunch of living teddy bears. Darth Vader, on the other hand, is someone to worry about.
- Season 1 of Agents of S.H.I.E.L.D. had a pretty steady set up, with May and Ward being orders of magnitude more badass than anyone else, and May slightly tougher than Ward. The next toughest was Coulson, who was more skilled than Skye but not by a huge degree. Fitz and Simmons were the Non-Action Guys, though Fitz was slightly more collected and effective in a combat situation than Simmons. This rough distribution was maintained in Season 2. Though several new agents were added who were all roughly as good in a fight as Coulson, but nowhere close to May and Ward. Skye got more skilled as time went on, but was still the rookie among the field agents, and Fitz lost whatever combat effectiveness he had as a result of Brain Damage. Shaken up further towards the end of Season 2, where the team begins working with superpowered characters who function as Glass Cannons to May's Jack-of-All-Stats.
- Averted in Kamen Rider Ghost, which shifts the power dynamic of its main trio a few times. Specter is stronger than Ghost when he first appears as The Rival (though the gap narrows over time), and later Necrom is stronger than either of them. Ghost's Toucon Boost form and Necrom's Redemption Demotion then result in Ghost becoming the strongest Rider, which is further cemented when Ghost gains Grateful form. However, Specter then gains the Deep Specter and Zesshou Specter forms, which makes him the strongest again until the debut of Ghost's Mugen form. Throughout all this, Necrom gains a number of minor upgrades but remains cemented in third place.
- Torg in Sluggy Freelance is arguably the lead, and is pretty much the weakest character on the strip until he got a demon slaying sword and Took a Level in Badass (which means he's still clumsy, but slightly less so). Riff, Aylee, Bun Bun and Gwynn are all far more combat capable, Zoë being the weakest character at this point.
- The Order of the Stick:
- The main characters are always seem to be at the same relative strength in battles. Roy is the power-hitting and intelligent fighter, V is the Squishy Wizard who can bring down absurd spells, Haley the sneak attacking Rogue, Durkon the Jack-of-All-Trades cleric, Belkar who is known in higher circles as Death's little helper, and Elan bringing up the rear as the Bard. While they have all taken assorted levels in badass, the relative competence between them all has remained static throughout. This is really noticeable after Roy comes Back from the Dead after over 200 strips. Despite the very act of resurrection taking him back a step and the rest of the party getting into adventures while getting him back he has somehow held onto his part of the party.
- It is also noticeable with the villains, most prominently with the Psycho Rangers the Linear Guild. Regardless of what they are doing between fights, every face-off is at least a fight. Z spend most of his time in jail and after that laying low while V was constantly fighting, yet in their rematch had V completely shutdown. On the other hand, Thog was thrown in a coliseum fighting whatever the Empire could throw in there, yet Roy was his equal in the rematch despite the handicap of spending most of that time dead. Also parodied, as one of Haley's old acquaintances deliberately became her nemesis in order to get a free level whenever Haley did.