Curse skills apply a variety of effects to your enemies in Diablo 3: The Rise of the Necromancer. The three curses listed her can be used for survivability, damage or utility. They all cost 10 Essence to cast and last 30 seconds. You can also make them permanent and reduce their cost with the Eternal Torment passive.

Decrepify

Blizzard Entertainment/Activision Blizzard

Reduces the movement speed and damage done of all enemies cursed.

Runes

• Dizzying Curse: Cursed enemies have a chance to be stunned.
• Enfeeblement: The initial potency of the curse is increased to 100 percent.
• Opportunist: Gain a small amount of movement speed for each enemy cursed.
• Wither: No longer reduces movement speed. The reduced damage is drastically increased.
• Borrowed Time: Gain cooldown reduction for every enemy cursed.

Leech

Blizzard Entertainment/Activision Blizzard

When attacking an enemy that has been cursed by Leech, you or your allies will be healed.

Runes

• Transmittable: When cursed enemies are killed, the curse will spread to additional enemies.
• Osmosis: Gain additional life regeneration for each enemy cursed.
• Blood Flask: Reduces the cooldown of you potion for each enemy cursed.
• Sanguine Ends: Whenever a cursed enemy dies, you will be healed for a small portion of your life.
• Cursed Ground: Curses the ground. Enemies in the cursed ground heal you.

Frailty

Blizzard Entertainment/Activision Blizzard

Enemies who have been cursed by Frailty will be instantly killed once they fall below 15 percent health.

Runes

• Scent of Blood: Cursed enemies take additional damage from your minions.
• Volatile Death: Cursed enemies explode when they are killed, dealing damage in an area around them.
• Aura Frailty: Can no longer activate. Instead, all enemies around you are cursed at all times.
• Harvest Essence: Gain a small amount of Essence when a cursed enemy dies.
• Early Grave: Enemies now die when they fall below 18 percent health. Cursing enemies now costs a portion of your life.