"With this character's death, the thread of prophecy is severed. Restore a saved game to restore the weave of fate, or persist in the doomed world you have created."
You can also use him for the quests THEN kill him. Personally I think that plotline is mostly funny in the pure absurdity of his character, but like many things in that game (crassius curio anyone?) he's pretty damn sketchy to say the very least. Personally my fave councilor out of all three houses is Aryon, who is significantly less sketchy.
The struggle of wanting to kill Alexander early to just have the talisman he drops, but knowing if you wait til end game, that talisman is even better.
Had a Morrowind run where I borked the main quest, sold or dropped the shadow shield somewhere and can't find it. The last save with it was like 10 hours earlier.
I didn't like the faction so I killed everyone including the future NPC questgiver. Once I progressed the main story, the quest marker would point to a floating point where their head would be, and you could hear the dialogue of the all the dead NPC ghosts taking to eachother.
5 years later and still not fixed so I still haven't beaten the game or played the DLC's. Didn't feel like starting from the beginning and risking the bug again.
As I started to hit a massive wall in the DLC, I started to look at helpful items. Turns out I never even saw Boggart in my first playthrough and in the second one... well, I currently did a fist weapon only run.
And I never did his early quest to begin with, missed it both times and never knew he would sell stuff at all.
He does? I must have missed that, the quest of collecting all Gwent cards was failed automatically as soon as the Baron died without me collecting his Gwent card