For all monsters you can get 460 charm points.
Doomsay cultist - 30 charm points
Acolyte of Darkness - 30 charm points
Bride of Night - 50 charm points
Nightslayer - 50 charm points
Midnight Warrior - 50 charm points
Midnight Spawn - 50 charm points
Shadow Hound - 50 charm points
Herald of Gloom - 50 charm points
Bane of Light - 50 charm points
Duskbringer - 50 charm points
If one of the laterns will turn off in all cities you will be able to meet Essence of Darkness. If world will win the event then you will be able to meet in every city Spirit of Life. You can't kill any of these 2 monsters.