Should know that Apocalypse isn't even the worst legendary weapon in FE6. I'd honestly place it in the top 3 divine weapons of that game.
EDIT: It's been a while since I've been ninja'd in this thread.
The big question here is how on Earth did Saleh end up being the last pick of the 3rd round of drafting? I mean, Marisa and Syrene were picked before Saleh. What's up with that?
EDIT: Neimi was picked before Saleh as well!
You need to have your thief's speed stat be equal to or greater than the speed stat of the enemy you are trying to steal from in order to steal from them.