Arelith

I was doing the Herald of the Storm writ and I got a double spawn of Stormherald at the end. Tried to do a careful pull of one of them, managed to draw him a few corridors away.. and he despawned. Shrug. Attacked the duplicate Stormherald, got him down to Injured and he also despawned.

Neither of them died but I have credit for Objective 4 on the writ.

The Stormherald teleports away when sufficiently hurt (this completes the writ goal). If you're not close enough to him when it happens, you wont hear what he says before he leaves. The double boss spawn is an old bug, however. Unrelated to this specific npc.