[It's fair to assume that if it's a sci-fi concept, Jupiter Jim has done it.

Unfortunately, Accelerator is jumping straight to the hard questions. Leo answers them in order.]

His name's Casey Jones. He's... well, I think he's the son of one of my friends from my world. Her future son. [In case that wasn't clear.] He knew all of us from the future and they have the same name, so it's a safe bet.

[If anyone would name their kid after themself it would be Cassandra "Casey" Jones.]

My little brother sent him back. Well, the future, adult, apparently basically a wizard version of my little brother sent him back, because it turns out that's a thing that he learns how to do! And...

[Leo looks a little uncomfortable with this next part, but, well, Accelerator might as well know. He's told everyone else important to him about it.]

I... don't know what happened to him - because I got brought here. And I'm not sure he would want to go back even if we found a way. [Leo folds his arms across his chest.] He said... in his time, everyone is dead.

[Yes, including Leo and Donnie.]