quick question re: sauron, ironman, destruction

[fizzix]

If you cast destruction with sauron or morgoth in it they get removed from the level. (or is this not right?) But when you come back again, they've returned.

What happens if you're playing ironman and you destruct sauron? Are you stuckk forever on dlevel 99, or will he eventually respawn?

[Psi]

I accidentally destructed Morgoth in an ironman game of FA. Thankfully he reappeared when I deliberately triggered a summoning trap. I'm told he would have eventually respawned anyway though. I'd guess it would be the same in V.