In full flow and under optimal conditions you are a threat battery. It's an unavoidable part of playing a shadow priest and one which you'll need to master if you are to avoid getting squashed twenty seconds into every encounter. Admittedly, it's something I'm still working on...
What is threat?
The first part to mastering our threat is to understand it. Basically, threat is a measure of an NPC's aggression towards player characters. Under normal circumstances, NPCs keep a 'hate list' of people with threat towards them and attack the one at the top of the list. But they don't switch targets the instant one player's threat tops another. There is a buffer, or more accurately, two buffers, depending on how close you are to the mob. In melee range, the mob will switch target when one player's threat exceeds 110% of the threat of its current target; at range, the mob will switch target at 130% of threat.
We build threat through the actions we take while in combat, and we can conveniently lump threat into two types, so I can use some bullet points and break up this big chunk of text:
- Damage threat — if you hit a mob, it will naturally be unhappy about it. One point of damage equals one point of threat. This threat applies only to the target of the attack. Just being in the vicinity of a mob does not cause threat — it simply places you on their threat table with a threat of zero.
- Beneficial threat — threat caused by beneficial things, which most commonly means healing and mana regeneration. This is calculated at a rate of .5 threat for every point or health or mana returned. This threat is divided equally among all of the mobs that are aware of you. So if you heal a tank that is being attacked by 5 mobs for 100, you will generate 50 threat or 10 threat per mob. It's this amorphous threat that usually causes stray mobs to peel off and hunt you down.
How do I generate threat?
So shadow priests face a triple whammy of threat from the damage, healing and mana regeneration we put out. Often, this is mitigated somewhat by the fact that over-healing generates no threat, nor does mana regeneration for non-mana users. Nonetheless, you will be generating considerably more threat per point of damage than any other class in your group — except, hopefully, the tank. This is especially true in fights with aoe damage, such as my nemesis Quagmirran in Slave Pens. In a worst-case scenario, with four other mana users in your party and all players taking splash damage, you will be generating threat before modifiers of:
damage done + (15% of damage done/2 x 5) + (5% of damage done/2 x 5) = 150% of damage done
(somebody please show me how to write that in a sensible equation)
On top of your standard dps spell rotation, also bear in mind the following things:
- Mind flay apparently carries a threat 'bonus' — probably because of the snare effect — although I have been unable to discover how much.
- Shadow word: death does no additional threat. However, in a threat-sensitive fight, if you heal the damage done by the spell's kickback through vampiric embrace it will clearly add to your agro. Similarly, the healing from prayer of healing, should you trigger it, counts towards your threat. It's sometimes better simply to remain at full health.
- Power word: shield generates about half the threat of healing per point absorbed. Not that this shitty little bubble is going to make a difference in heroics. But if you can spare the mana, it will help mitigate the damage of pulling threat by giving your healers a slightly bigger cushion and minimising the gap your tank has to make up.
- Power word: fortitude and prayer of fortitude will generate threat if cast in combat. I think it's roughly the equivalent of healing the amount of hit points the spells provide.
- Mind control has a bonus threat value. Don't ask me how much it is. It's big though. It's like you kicked them in the nuts and called their mother a ho.
- Spell resists don't apply threat, but they put you on the target's threat list. So if that mind soothe is resisted, your tank better be ready to jump into action.
Threat management for all dps classes starts with the talent spec. Every raiding shadow priest should have three points in shadow affinity, reducing your threat by 25%. This isn't the best threat reduction talent in the game but it's better than nothing.
The next thing you should do is download a threat metre and keep it up to date. I recommend Omen (get the latest version from files.wowace.com). Threat metres give you a visual representation of threat in real-time and provide alerts when you reach preset thresholds. Preferably, all players in your group should be using the same metre; at the very least, you should ensure your tank is.
Know the encounter. Some fights are very threat-sensitive. Mobs may have abilities that wipe the threat table, deliberately target players who are second in threat, or not have threat tables at all. Get a more experienced player to explain the fight first or read up about it in advance on sites like wowwiki.
Play intelligently. First of all, give your tank a break and let them get a head start. Paladins are very good at top-loading threat so you shouldn't need to worry so much with them. Make sure you have an established kill order and follow it. Focusing fire on a single target helps the tank keep ahead of you on threat. If you go around dotting anything that moves you can't blame the tank if you wind up dead. Alter your spell rotation according to the encounter. Vampiric embrace is a spell you can often do without, and it will save you a considerable chunk of threat. Dropping mind blast and shadow word: death will reduce your spike damage and make your threat more predicable. And if aoe threat is an issue, dropping vampiric embrace will ensure that all your threat builds up on a single target, although you'll run out of mana pretty quickly if you go down this route.
You can also benefit from a couple of party buffs if grouped correctly. If you're lucky enough to group with a paladin, always ask for a blessing of salvation. This little gem reduces your threat by 30%. And a shaman can sometimes drop a tranquil air totem in threat-sensitive fights. This is a tricky one though because it affects the whole party in range, effectively cancelling out any threat-reduction gains if it falls on the tank too. In raids it's not so bad, because you probably won't be in the main tank group, but in 5-mans it's usually unworkable.
Finally, there's also a cloak enchant called subtlety which reduces your threat by 2%. The enchant is available from Thrallmar and Honour Hold and requires exalted reputation and the mats are not that bad. It's the only decent enchant for the slot anyway so you have no excuse not to get this.
If you do find yourself with too much agro, there's not an awful lot you can do about it. Clearly, the first thing to do is stop attacking, but with your dots still running this will be of limited value. Your main fallback is the rather controversial ability fade. The tooltip for this spell reads "discourages enemies from attacking you" which is misleading at best. What it actually does is reduce your threat on the tables of all mobs who are aware of you by a fixed amount; at rank 7 this means by up to 1500 (remembering you cannot have negative threat). This lasts a paltry ten seconds, after which time the 1500 threat is returned. To start with, there's no guarantee that fade will work — sometimes, you remain at the top of the threat list even after the reduction. And if you and your party don't deal with the situation within the time limit — either by killing the target or re-establishing proper threat — it could come straight back to you. The other problem with fade is what happens to the mob once you shake it off. It might turn back to the tank, but the healer could well be the next person on the threat list. That makes using it in tight spots a gamble that sometimes isn't worth taking. Either way, this is not a spell you should rely on for managing threat.
Certain items can also provide a temporary threat reduction, similar to fade. These are on-use effects and come with a cooldown of a few minutes each. The hypnotist's watch and spore-covered drape are two very easy items to get hold of, while the jewel of charismatic mystique drops from grandmaster vorpil in Shadow Labs. With no spell damage, they will gimp your dps but not by nearly as much as dying.
Finally, the shrouding potion will reduce your threat by about the same amount as fade, only permanantly. The potion is craftable by alchemists and the recipe is available from Sporeggar with exalted reputation. Unfortunately, it shares a cooldown with mana pots, making it less than desirable for the oft-thirsty shadow priest. (Thanks to Grayhammer for some of these tips.)
The last drastic recourse available to you for ditching threat is death. That's one sure way of wiping the threat table. Clearly, this is not a practical (or affordable) approach to maximising your contribution to the party on a regular basis. However, with the use of a soul stone or druid's combat res it is possible to deliberately go all out on damage knowing you will be given a clean slate after death.