Has Siegmeyer jumped down with you and given you his Speckled Stoneplate Ring with all the "What a fight!" dialogue stuff?
Have you rescued Sieglinde at Duke Archives?

He never jumped down with me to fight in Izalith, he just commented on how I defeated all the abominations. I killed them all before reaching him. But I thought he leaves the area after

Then it isn't bugged and you've just messed up his quest until the next game cycle.

There's a little cutscene, where he jumps down first, if you talk to him, before killing all the monsters. He then needs to survive the fight, which is pretty tricky, since he goes first and dies so fast (best to kill all but one of the monsters first with a ranged weapon).

Originally posted by JellyPuff:

Then it isn't bugged and you've just messed up his quest until the next game cycle.

There's a little cutscene, where he jumps down first, if you talk to him, before killing all the monsters. He then needs to survive the fight, which is pretty tricky, since he goes first and dies so fast (best to kill all but one of the monsters first with a ranged weapon).

oh no! ahh damn, I should have left one alive
ty for the answer though

It's impossible that nowadays people still think that Siegmeyer and Siegward are the same person.

the siegmeister