Personally? Only a handful. I've got a bunch of half-siblings that I found out about when I got to camp - I go to a camp for demigod children. I didn't really bother counting how many there were and I don't remember all their names. And there were a lot more who had a different godly parent than I did.

And then there's another camp on the other side of the country for demigod children of the Roman gods. There were hundreds of them, but I didn't get to meet many of them. Then I kind of got possessed and attacked their camp which started a war. [Leo claps his hand over his mouth. That was way more than needed to be said. It wasn't something he liked to talk about and he still feels guilty about it.]

Why did I say all of that? [It finally dawns on him that this must be one of the curses he heard about. He's not a liar, but he does withhold information a lot.]