I’d go with the fifth one. But if you feel like creating a new name, try some other words, such as:
- bane
- death
- despair
- undead
- scourge
- sorrow
- illuminati (might sound very ‘mainstream’ and not too original, but it works well)
- hail (of) (undeath, venom, flesh, etc)
- skull
- anti-
- unspeakable (horror, etc)
If I come up with any new words that could help you, I will post them. Have fun choosing your name!