
Destruction Warlock can spend 5 points in
0/13/58 spec to bring Replenishment (via
Improved Soul Leech) to the raid.
Replenishment gives 10 party or raid members 0.25% of their maximum mana every second for 15 seconds. It is recommended to have minimum one replenishment class for Ulduar 10 and two for Ulduar 25. The buff is especially helpful to healers.
Other choices are
Shadow Priest -
Vampiric TouchRetribution Paladin -
Judgements of the WiseSurvival Hunter -
Hunting PartyFrost Mage -
Enduring Winter