Sylar from Heroes
The concept of an ability thief is fairly common. There are different levels of the ability as well, which can range from killing the original owner to simply copying it. Guess that makes the ‘thief’ part not true since the term implies that the original owner no longer has the ability. Anyway, I thought this would be an interesting concept to explore.
This power tends to be held by villains, especially if it involves killing the original owner. I see it a lot in anime like ‘Yu Yu Hakusho’ and ‘Hunter x Hunter’ . . . Come to think of it, those were made by the same person. Anyway, there’s also the old series ‘Heroes’ that used this for their top villain. All of the characters become deadly adversaries who have a multitude of abilities, which means the heroes don’t know what they are going to get. It can get worse as the story progresses since the villains don’t stop gathering powers and will continue getting stronger. It almost puts a timer on the adventure because there will eventually be a point where the ability thief is unstoppable.
Authors can go too far with this, especially if they don’t reveal all the stolen powers. This gives them an easy out for letting the villain win or simply survive. All you have to do is give them an ability that solves the problem. Same can be done with heroes, which means the threat of defeat is nullified. The only way to stop them is to have them lose their stolen abilities, which is a challenge and ends up destroying the character. Having them set out to gather more abilities from scratch can make a reader wonder if they have any purpose other than stealing powers. So, this type of villain or hero can lead an author down an iffy path.
I talk about powers, but this can be done with other traits. There are characters who can steal fighting styles and various skills. It isn’t on the same level as the power/magic thief, but it works off the same principle. They’re basically mimics, which I would put in the same category. In fact, the ability thief is the same as the mimic, but there isn’t always a physical change. People tend to think of mimics as shape-shifters that steal the identities and abilities of others. The ability thief remains the same unless a physical change is part of the stolen ability.
Personally, I like this power, but I don’t like seeing it used so often. It can be very broken and a long-running story seems to always require the ability thief become almost god-like. This results in their defeat being unbelievable. I like them more as short-term enemies or obstacles, which means they can’t grow too powerful. If they’re heroes then I prefer to have a cap on their abilities. Although, I think a heroic ability thief is easier to work with since an author will have to establish their repertoire and can’t pull a surprise power out of nowhere. The hero doesn’t get as much time away from the audience as the villain, so it’s harder for them to secretly go god-like.
Not sure if I’ll ever attempt one of these characters. I did have a similar concept in mind with a character who had a different power depending on the personality that is in charge of the body. Unfortunately, I started seeing that turn up in comics and other stories, so I haven’t touched the character for about 20 years. Still not an ability thief, which is still something that I’ve seen so much that I don’t think I can do anything unique with it. Not enough for me to feel like I’ve added to the overall concept. With a concept like this, I would like to try something new since it has so much potential to go off the rails. Guess I’ll have to tinker with the concept when I get an opportunity.
So, what do other people think of ability thieves or the concept?
Legends of Windemere 
Sylar is a great example of this. The tension of whose ability he would steal next and how the other characters tried to stop him from connecting to characters like the cheerleader made the whole season great. Rogue also was in some great stories. But these characters seem to outstay their welcome sometimes as you mentioned when they become too overpowered. Taskmaster had the ability to duplicate another character’s movements, but there were limits to his ability. Maybe that is a way to avoid a character being too overpowered.
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The overpowered issue is the big one. Temporary usage tends to help since they can’t keep powers for long. Another one is that they can only copy a certain amount, so a new power requires the ditching of an old one.
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I like the ditching of old powers. That keeps things a little balanced and could put the thief at a disadvantage in some cases, especially if the last stolen ability is one that has to be sacrificed at the worst possible time.
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I’d make it slightly fair by having them choose the ability they give up. Thinking about Neito Monoma and his copy quirk in ‘My Hero Academia’. He can only activate one stolen quirk at a time and they only last 5-10 minutes. There are other limitations to what quirks he can copy, which keeps him in check.
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I think it would be fun to read about a hero who was a victim of power theft. A good story would be how the hero got the powers back.
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Captain Marvel kind of had that when she was Ms. Marvel. At least in the comics. Superheroes always seem to lose their powers at some point.
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Superman and Kryptonite is a great example.
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I have a lot of skepticism about stealing or copying someone’s powers, too. Especially if they’re supposedly copying a skill just by watching someone. To take an example from the two major comic companies, how would you “copy” from Batman, who took years to develop his prowess? Or how would you “steal” Captain America’s abilities, which are based on a secret chemical formula and years of training?
If I was going to do something like that, I would definitely put in limits. Maybe the stolen power only lasted an hour, or they could only steal one at a time and the other was gone. As you say, it would just be ridiculous if the thief could “copy” a library of powers.
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With fighting techniques, the answer is usually a character who has a power or mental specialty to copy on sight. They usually have been doing it for so long that they have basic knowledge of various styles themselves. Taskmaster is the best example. That’s just with fighting styles and skills though. Superpower copying typically happens due to another power, which usually has limits.
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I agree that it’s been overdone, and would be hard to pull off. It might be interesting if the persona and emotions were also part of the deal. After enough people occupy the villain’s head, he loses his mind to the point of becoming comatose.
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The ‘too many stolen psyches’ thing has been used before. Rogue dealt with it. Midoriya in ‘My Hero Academia’ has the psychic ghosts of the previous power holders in his head. The only issue I see with it leading to becoming comatose for a villain is that the heroes only need to wait for him to take himself out.
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Maybe the user knows that one more time will kill him. What heroic deed will be enough to make that major decision?
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Could work as a big sacrifice moment.
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