Some people treat villainy as a full-time profession, others as a hobby. A few people dive off the deep end and go full villain, taking it on as their full time identity. That's fine, but here's a few things to remember. Some of them you really should know by now if you're in the game.
First, a word on super-biology. The super mutation is something you get if your mother had the potential for it. The father doesn't really enter into it as far as science can tell. But, if your mom had the potential, all of her kids will have power too. Let me tell you, this discovery really threw a monkey wrench into countries where giving birth to girls was frowned on - and it's probably going to topple a few regimes after a few generations of super-girls come into their powers. There's a ton of opportunity here for the right sort of person. But I digress.
Second, family is a weird thing. Parents are something more than human to their kids already, and siblings can fight for years, or feel responsible for each other, in weird ways that defy explanation. I'm no psychologist, I've just seen it happen too many times to think it's a coincidence.
Third, as you progress up in stages, your lifespan will get longer and longer. Conservatively, a Stage 2 super has an average life expectancy of about 150 years, and a Stage 3 has twice that, and so on up. I want that to sink in. You may be young now, but you'll stay young. If they're telling stories about you now, they'll be telling stories about you in decades and you probably won't have changed a bit.
What does all this have to do with identity? Simple. The lesson here is: if you have living relatives, protect yours. Don't use your real name. If your real name is really cool, sorry, but think of something new anyway. Wear a mask, or a full-concealment helmet or something.
Who remembers those headlines from the 80s? "Eastern European super-baby factories raided". That stuff. Let me tell you what happened there. I wasn't in on that deal, but I know people who know the real score. Some supers' mothers and sisters were being abducted from their very homes and taken to other countries, and forced to give birth repeatedly. The kids were going to be brainwashed into super-powered drones. That didn't happen, because people got wise and raided the whole operation.
Every villain reading this today should be grateful that happened, too. This stuff is pretty dark for everyone I know. Plus, if that had run its course, I don't think modern villainy could exist. We'd be facing some kind of crazy military crackdown on people with powers. But everybody reading this should also remember: it can still happen, maybe on a smaller scale, but it could happen and might still be happening. So even if you don't give a shit about your family personally (you heartless jerk!), you should care because it could still affect you.
Aside from that whole unhappy chapter of history, super-siblings may decide to come after you. They'll have some misguided ideas about "bringing you back" or "making you remember the good times" or whatever convinces them that you need "saving". Or they might decide to try following you into villainy. Sometimes this is cool - provided they aren't useless. Often it isn't, and you are stuck with someone who idolizes your style but gets in the way of you doing your thing. Nobody wants that.
And remember what I said about longevity? If you get stuck in one of these situations, it will probably be going on for a long time. And I mean a long time. Don't let it happen to you!
Mr. Big's words of wisdom: protect your identity, for the sake of your family or at least your own sanity.