Demon twins but is that one manga (My Gemini) where twins switch places until in one of those switch one of them dies.
The two still in the League of Assassins, they train them in different fields and sometimes even treated different because of it.
Damian is jealous of the freedom the League seems to give Danyal and grows to resent Danny until Danny offers to switch places. They might not be close, yet Danny loves his brother and knows his "freedom" is not exactly what it looks like.
Danny just wants to get along with his brother.
So they switch places now and then, they take it as a form of training and are surprised no one notices. They grow close as Damian can now see Danny was as restricted as him.
They get to know each other as much as they can to never being found.
Then it happens; in one of those switch "Damian" is killed. They were attacked, they were together, it wasn't supposed to happen. Danny took the hit instead of Damian.
Talia loves her sons, no matter how twisted that love is. So when trying to revive Danny didn't work— he never came out of the Lazarus water— she shipped Damian to Bruce to keep him safe from the League.
Now Damian is stuck acting as his twin brother in an unknown place. It makes him feel close to Danny but also so alone too.
If Damian is Danyal then he wouldn't try to kill Tim, Danny wouldn't do it. If Damian is Danyal then he wouldn't want to be Robin, he would want to have his own mantle or not even have one (he is tired of always fighting). If Damian is Danyal, he would try to get close to their siblings, seeing them as such.
All of it and more goes through Damian's head each day.
Meanwhile Danny finds himself in the other side of the world, being taken in by a family in Amity Park.
