I went into the Umar Hills, and when I went to the cave with the mimic, there was a purple dragon outside. I killed it, and Saerileth said that we should go to the Order of the Radiant Heart and report back to Sir Havun Clarenshide. There is also an automated journal entry that pretty much says the same thing.
But I have no idea who Sir Clarenshide is. I've never encountered him. And when I go to the Order of the Radiant Heart, he is nowhere to be found, either inside or outside.
How do I spawn him, and how have I, if at all, messed with Saerileth's quests and romance?
EDIT: I've been able to spawn Sir Havun. When I talk to him, he thanks me for killing the dragon, and then asks me to kill a bunch of vampires below the graveyard. Accepting the task starts Chapter Thrree, so I didn't save the game, and I'll spawn him at some point in the future.