Unholy Frenzy

Unholy Frenzy is an Unholy Death Knight ability that causes the target to lose 20% of its health over 30 seconds, but its melee and ranged haste is increased by 20%. With the changes to haste affecting resource generation since 4.0.1, all non-caster classes receive good effects from this.

Usage
When soloing, consider casting it on your Ghoul to save your own health. Even when using it on yourself, you get 1.8 runes from it if flat calculated, so you should have no trouble Death Striking that health back against regular mobs.

As the changes in 4.0.1 for haste now affect resource regeneration as well, this is effective on all of the following:
 * Warriors: More haste means more weapon swings means more rage, and also more global cooldowns to stuff rage-abilities in. It is not optimal because cooldown-based abilities like Mortal Strike or Raging Blow are not reduced in cooldown, so the extra rage will likely be spent on Heroic Strikes. For Tanks the same holds, so an increase in threat regeneration at the start of the fight could certainly be worth the extra healing needed if the tank has trouble holding aggro, and the lack of a resource cost means Unholy Frenzy is usable then.
 * Paladins: Haste reduces the cooldown on Crusader Strike or Divine Storm for Retribution Paladins with the Sanctity of Battle talent, generating more Holy Power and thus more Templar's Verdicts or Word of Glories. Other cooldowns such as Judgement remain unaffected, so its efficiency is about on par with warriors, pretty good. It's usage is further enhanced by the Mastery Hand of Light, and the talent Divine Purpose. When coupled with Zealotry and/or Avenging Wrath this can be quite the burst, very usable in PvP as well. Usage on Protection Paladins is not advised, as they do not have Sanctity of Battle, so only white damage is affected.
 * Death Knight: Rune regeneration is affected by haste, so they regenerate at a 20% faster pace. Death Knights in Unholy Presence can not further reduce their global cooldown and will have plenty of buttons to mash in the time this buff is up, switch to Frost Presence for optimal effect; although in PvP, the run speed could be worth the loss in effectiveness. More runes mean more runic power mean more Death Coil (death knight ability)s, Frost Strikes or Rune Strikes for tanks. As such, all specs benefit fully from being hasted, but as with the other tanks the damage could put a bit of strain on the healers' mana. It could also be used on a Risen Ghoul, but even when glyphed, specced, and Dark Transformationed, this is not better in damage, however it puts no strain on healers and can thus be safely used whenever.


 * Hunter: Focus regeneration is increased by ranged haste, so apart from some few-used cooldowns in PvE like traps, the Trap Launcher, and Concussive Shot, they get full effect from Unholy Frenzy. When the healers are strained, you can instead opt to Unholy Frenzy their pet, as a Beast Mastery pet dishes out almost as much damage as the hunter themselves, has increased focus regeneration like him, and also helps the hunter with talents like Invigoration. For non-BM hunters, just put in on your own Ghoul.
 * Shaman: Only the Enhancement Shamans have any use for this ability, but it is poor. Not Shocks nor totems nor their melee strikes are enhanced by haste as they are all cooldown-bound. Only white damage is buffed. Not a good choice.


 * Rogues: They get increased energy regeneration from haste, and energy is the limiting factor for rogues' attacks per minute. As a rogue can hold up his Slice and Dice, Rupture, and if needed an Expose Armor with his own energy regen, it will result in more combo point-generating moves like Mutilate and Sinister Strike, as well as instant damage finishers Eviscerate and Envenom.
 * Druids: Cat druids get increased energy regen like rogues, and Bear druids get more rage like warriors. The same holds for their paragraphs, cats get more direct damage finishers and bears get a bit more threat at the cost of health, and thus healer mana. Unlike the others, the Feral talent Leader of the Pack causes them to regenerate the lost health through critical strikes effortlessly.

When in a raid, use this and some dpsmeters, or just ask someone who the best damagedealers are, to find out who to cast this on. Chances are big you yourself are not the best choice for your ability, about 7/8ths (3 tank, 8 melee/hunt, 8 casters, 6 heal or so the normal 25man composition)