Warlock · talent ability, from Wrack

Wrack

211per cast

Rank 1 · level 60 · before talents

Wrack

200 Mana30 yd range

Instant

Tears the target apart from within, inflicting 36 Shadow damage every 1 sec and increasing the damage they take from your other Shadow damage over time effects by 10% for 6 sec.

Talents that change it, each at full ranks:

Soul Siphon · with 3 of your Affliction effects on the target +76.0 Demonic Knowledge · with a demon +50.3 Improved Drains +42.2 Improved Shadow Bolt · after a Shadow Bolt crit +42.2 Master Demonologist · with your Imp or with your Succubus +21.1 Malediction +10.6 Shadow Mastery +10.6 Suppression +6.6 Malevolence +5.2 Pandemic +3.6

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