Raiding Shadowpriest DPS utilises roughly five core spells for DPS. In order of uptime priority, they are:
Shadow Word: Pain
My personal opener, since it requires on equip effect procs (Black Magic): MF VT MB DP SW:P
Try to make sure VT is up before MB for Replenishment uptime. Start casting VT when there is about 1.5s left (adjusting for haste).
Some people use Shadow Word: Death in their rotation; I prefer to save mine for movement situations.
MF is a filler spell that has damage ticks at about 50%, 75% and 100% during the channelling. So always make sure you have casted halfway before clipping the spell if you need to. MF also provides a stack of Shadow Weaving every tick. This also applies to the Muradin's Spyglass trinket (unfortunately only provides a single stack per cast for Illustration of the Dragon Soul and Eye of the Broodmother).
DP's instant cast component is very powerful, especially with heroism where you can almost keep casting it, waiting for the first tick and casting it again. This is probably only something you can do with T8 2set bonus though.
Hard refreshing SW:P through recasting it (as opposed to MF's soft refreshing it) can be useful when:
- You possess a crit buff through Potion of Wild Magic and/or Nevermelting Ice Crystal.
- You have a Rune of Power/Malygos Spark damage buff.
- Your current SW:P wasn't casted with 5 stack Shadow Weaving.
Hard refreshing SW:P doesn't have any affect on:
- You gain spellpower buffs. It adjusts automatically.
- Any boss weakened/debuff states.
During Heroism: Leave out MB from rotation, be sure to cast VT/DP as soon as it starts and just before it ends to get full benefit from the haste. Otherwise make use of any potions and MF the day away.