Soul Link

From WoWWiki

Soul Link
Soul Link Instant cast 100 yd range 16% of base mana When active, 20% of all damage taken by the caster is taken by your Imp, Voidwalker, Succubus, Felhunter, Felguard, or enslaved demon instead. That damage cannot be prevented. In addition, both the demon and master will inflict 5% more damage. Lasts as long as the demon is active and controlled.
Usable by
Class	Warlock
Properties
Type	Offensive, Defensive
School	Shadow
Cooldown	None/Global Cooldown
Talents
Talented	Yes
Talent tree	Demonology, Tier 7
Talent required	Demonic Sacrifice
Other information
Ranks	1
Requirements	Must be controlling a demon.

Share the pain!

Soul Link is a warlock Demonology talent and spell, which redirects damage from the warlock to its minion, and increases damage done by both.

Rank	Mana Cost	Level	Cost
1	16% of base	40	Talent

Notes

If a Warlock's demon is Banished, this effect will be removed until the demon is back under control of the master. The druid spell Cyclone also temporarily suspends the Soul Link effect if cast on the demon.

Past changes

Patch 2.1 - "Adjusted tooltip to explain that the damage transferred to the pet cannot be prevented. The functionality remains unchanged. This ability will now work with enslaved demons."

Prior to Patch 1.8, it redirected 50% of all damage and lasted for 30 seconds, but was dispellable.