Stygian Fury

Stygian Fury have a ranged magic attack unlike regular

Succubus monsters which use a melee attack.

Stygian Fury also cast several different curses.

Amplify Damage
This curse is the same as the Necromancer's Curse.

Weaken
This curse is the same as the Necromancer's Curse.

Defense Curse
If you have more Life than Mana, then they give you a curse that halves your defense (65% in Nightmare, 85% in Hell).

Blood Mana
Succubi and

Baal cast a special curse shown in the screenshot below (Along with Thunderstorm and

Energy Shield). This curse causes you to do damage to yourself when you cast spells. For skills that require more mana, you will take more damage. This even includes such spells like

Teleport but doesn't include Thunderstorm or

Energy Shield because you already have cast them. Whenever this curse is cast on you, stop casting spells until it's worn off, click on a Shrine to counteract it, or go back to town and have it removed. Blood Mana only affects you if you have more Mana than Life. If you have at least as much max Mana as max Life, you can be cursed.