My fight with Yser was far away from conventional. I was fighting him around level 6. Part of my 7 party members party died during the process near his spawnpoint, and when the situation turned really bad, I drove the rest far away from him and waited for the combat to end (to reset hp and skills ). I was able to kill all of his warriors but one, and during the second retreat Yser just killed himself. Exploded. Log showed that Yser Berathianxyz (or whatever) destroyed Yser Berathianxyz. While he exploded he was following my retreating characters - I have a suspicion, that while he was targeting one of them he lost the target and targeted himself instead (?). There was no skill name though (see attached screenshot).