Problem with NPC respawning (ascent)

I'm really new with running ascent. I spawned Onyxia in IF with the .npc spawn <ID>
I tried .kill but she respawns. I tried .npc return and tried to restart the server but she keeps respawning. Anyone know the command so she won't respawn in IF after killed?

Thanks for the help.

.npc del
(.npc delete)