Inherited Powers System, MHA Style

I need to get another idea out of my head so I can focus on things more urgently, let's do this.

Superpowers are fun. Superheroes are fun. Though you could also maybe have these featured in non-superhero-centric games, but that's beside the point. Ever since binging My Hero Academia with my wonderful girlfriend, I've wondered how would I translate stuff like this into a tabletop roleplaying game ruleset. To give a brief overview, the powers (called quirks) are mutations that keep getting wilder over the generations, there's a large variety of them, and most people seem to have one quirk each. Just to be clear, for this thought exercise, I'm ignoring the cases of more than two quirks in one person, like the blonde guy from the 1B class or some spoiler characters. No meta-quirks that manipulate the quirks.

Now that the summary of the anime's premise is done, I'm gonna go back to calling them Powers, because I prefer that name. Quirk is fun, but in TTRPGs it tends to stand for something else. I hope you'll enjoy this, and have a wonderful day!

Sidenote: Anything below isn't set in stone, it's just a proof of concept for now, barely functional for a game.

Superpower, by Dan Su

Inherited Powers System

The Powers are generally inherited from the parents, though sometimes they can be manifested completely spontaneously. Since they are genetically based, they are made up of several components:

• Trigger
• Ability
• Limitation

In a usual approach, you'd just get a bunch of points to spend on each of these, and be done. Boom, there, you got your Power, now you can go fight crimes. But as it is becoming obvious to me, some people love to gamble by rolling the dice, if there's a chance they could get some kind of an advantage out of it. So let's mix the game design with worldbuilding. Here are guidelines on how you could inherit your Power from your parents.

Everyone has two of each of those, one dominant and one recessive. There isn't any ranking as to which traits are more dominant than which, this is all just about pure luck of what one is born with. So, get a pair of color-coded dice, let's say 2d20's: one for dominant traits and one for recessive traits. Roll them for each parent's every trait (Ability, Trigger, Limitation). The higher roll defines which gene is passed onto you from that parent. If both rolls are equal, congratulations, the gene mutated and you instead get to roll on a random rolltable for that trait! (If I weren't busy with other stuff like preparing for a One Piece trishot, I'd make one, but I'll leave that for another day.)

After this is done, you should be left with a pair of Abilities, a pair of Triggers, and a pair of Limitations, one from each parent (unless they mutated). Now, assign the colors to your parents, and roll once for each pair. The higher roll determines which of the traits is considered dominant for your body. If both are equal, congratulations - you get to keep both somehow! ... look, anime makes it work for Todoroki, so I might as well include it in this ruleset.

If you want "quirkless" (or in this case Powerless) to be an option, that will occur when both rolls are a 1 on either Power or Trigger. You have a gene for it, but alas - the dominant one turned out to be a blank.

I did say that I don't have rolltables or energy to make them, but I might as well leave you with some examples. Of course, these are not complete in any way, I'd spend a lot more time if I wanted to make them complete.

Trigger

1. Always active (Invisible Girl)
2. Line of sight and focus (Eraser Head)
3. Voice and focus (Present Mic)
4. Touch and focus (Uravity)
5. Consuming something (Sugarman)
6. Focus (Creati)

Ability

I write them broadly, but with more time I'd make them extra 

1. Boost a personal characteristic (strength, speed, senses, ...)
2. Produce something (fire, sticky spheres, ...)
3. Manifest traits of an animal (frog, seal, ...). Maybe this one could come with limitations on what triggers are allowed with it.
4. Manifest a supernatural characteristic (invisibility, weightlessness, locking something in place, ...)
5. Transformation into and back from some substance (dust, paper, ...)
6. Area influencers. Not sure how this would be different from numbers 2 or 4, but I wanted there to be six items on each list.

Limit

I'm not sure if these shouldn't just come prepackaged with the Abilities and/or Triggers. For now, they are separate.

1. Time limit
2. Line of sight
3. One target at a time
4. Fuel consumed
5. Knowledge
6. Environmental condition

That's all for today. This could make for a neat core of a system. That being said, there is also a downside to this: One power per character can work well in a TV show, but it might not be ideal for a TTRPG. Depending on your Power, your character could fall somewhere in the range from "can resolve any situation on their own" to "one trick pony that needs support".