Priest · Shadow Magic · tier 4 · from level 25

Vampiric Embrace

Rank 1/1

Afflicts your target with Shadow energy that causes all party members to be healed for 20% of any Shadow spell damage you deal for 30 sec.

Doesn't change the damage or healing of any Priest spell.

Plan a Priest build

Averages, counting crits and misses, for a level 60 Priest with a typical weapon and no other gear or buffs, against a target your level. Worked out from the game's own data, the same way as the Foresight addon.