Undead (Technically) Demon Twin

Backstory because everyone loves knowing knowledge

Ra al Ghul had a daughter named Talia. Talia had a brief(ish) relationship with Bruce Wayne (a.k.a. Batman) that resulted in twins ( yes I said twins, first divergence from canon, woohoo, also yes that kind of fic) Damien and Danyal Al Ghul. They grew up in Nanda Parvati, only really getting to hang out with each other if they were training or fighting. Danyal found out only one of the twins was going to be allowed to survive as Ra's heir, the other would die. Danyal did not tell Damien about this and handled it the only way he knew how.

He convinced Ra to send him on a mission, made the mission go horribly wrong, wired a building to explode, killing everyone else who had come on that mission with him, and left enough evidence for everyone to believe he perished in the blast.

(Damien would have killed Danyal for the stunt if he didn't already believe Danyal was dead.)

From there Danyal changed his name to Daniel (yep, real different, but then again he was like ten at the time) and got himself adopted by the Fentons. Things went about as well as things can go with ghost-obsessed parents and he ended up a half a through a freak portal accident.

Things went okay for a few years until the Fentons (read: the adults, Jazz already knew) found out, freaked, trying to kill him/Phantom.

(Clusterfuck am I right?)

Daniel fled and ended up in Gotham, found out his twin was a Wayne and didn't tell said twin he was alive.

Shenanigans and a bit of robbery ensue.