Just a simple questing but with conflicted answers.
What happened after the War of Lorkan?
I know that Nerevar left Dagoth Ur and went back for the Tribunal's aid.
Upon their return, Dagoth Ur is corrupted by the heart.

What happened then?
Did the Tribunal get corrupted by the heart and kill Nerevar?
Did Dagoth Ur kill Nerevar?

Please help where you can.

Take this to the lore forums; you'll get a more sufficient answer there.