What made Drac drop the hammer?

The Nightwalker's claw wounds you.
Dracmael's beating DISMEMBERS you!
The Hammer of Muspellsheim slips from Dracmael's grasp and he drops it!
At the last moment you avoid Dracmael's cleave.
You keep Dracmael at bay with your polearm.
You keep Dracmael at bay with your polearm.
Your shocking bite MASSACRES Dracmael!
Dracmael parries your shocking bite.
A gleaming diamond circlet glows briefly, and the calm of Temperance gives you
peace.
Dracmael is gushing blood.


What made that happen?