A lot of people have been asking about the MC's age. I was going to answer that in future chapters, but since you're all so eager, I'll explain it here.
Originally, the MC was supposed to be a bit older—around 16 to 18 years old. Why? Because I find child protagonists a bit odd, and in my opinion, that wouldn't really fit Invincible, since the series has some pretty violent scenes for a "kid." But I wanted to start from the very beginning, with Eve still young and before she met Mark, so the MC could be her first boyfriend.
The problem is, I forgot that Eve awakens her powers pretty early. So just think of it this way: the MC is the same age as her, but he just looks a little older. He doesn't look like a muscular adult—just a teenager. And honestly, this doesn't matter much, since I'm not planning on having the MC and her get into a relationship yet.
As for other questions, like "Why did he reveal his true identity to her?"—because it doesn't make any difference. She would've found out eventually anyway.