Rare guard killed my quest NPC

[smajdalf]

In short: I can't finish the sun paladin unlock quest (Eight legs of wonder) because the quest giver npc is dead, killed by nearby rare guard.

The quest giver with a lot of random guards was standing next to this rare one, that periodically dealt damage to them. When I took the quest they were all about 1/2 hp already but I didn't realised what was happening, when I came back they were all dead.
Someone in the chat told me to try kill the game process and reload the latest save, so I did. The quest giver was still dead but I saw the rare guard kill the last two normal ones. I think it was through combination of Corona and Darkest Light sustainables - dealing damage on spell crit / when he runs out of energy.

Screenshots: http://imgur.com/a/PPNLf

The result is that I can't finish the quest and unlock the Sun paladin the first time I managed to get to Far East.