Reason for the "instadeath" of Nidhogg: The fight stops when he hits 5% health, so there is not really a death (hence quotations.) There are a few times this happens. Since we don't actually kill Nidhogg during the fight, there is no message in the logs.

As for why you died, I am guessing lag. If you kill the adds fast enough and get under the dome before Massacre casts, you should be fine. If you hit a lag spike at the right time, the server might think you didn't make it before the cast bar finishes.

Enjoy the rest of HW!!