Board Thread:General Discussion/@comment-29929311-20160912203904/@comment-24674051-20160913170411

Sadly, from a storyline perspective, There is no practical way to bring Robin back. By the current story, Robin was obliterated from existence (a story which I didn't buy then, and still don't buy now, since I think Hades was exaggerating to add emphasis to his threat). But even if Hades was lying about the erased from existence aspect, Robin is still dead and buried. and I think at this point, dead is dead, they played their ressurect card with Killian.

Now, as Esk pointed out, if the writers want him back, and if Sean wanted to come back, then they could find a way to do it. But for now, it's not in the cards.