I've had this idea for a social experiment in my head for the past few weeks, where you lock five priests together in a room with nothing but Highland Spirits and force them to have a round table discussion about Lightwell. While I work on my hypothesis and proposal -- and find a way to bait Fox Van Allen into this possum trap -- you guys can finish reading up on the finer points of healing Cho'gall as a holy or discipline priest. Seeing as this is the last boss of The Bastion of Twilight, this will be the final installment of Spiritual Guidance's priest healing guides for this tier.
Cho'gall is a two-phase fight featuring a long first phase that alternates between heavy tank damage and heavy raid damage for healers. The shorter, second phase is a chaotic burn phase that you'll have to keep under control, both with healing and execution.
As always, before we get started, you'll need to get acquainted with the fight. The fight is not terribly complicated for healers, but you can check out L2R's guide to Cho'gall if you're not familiar with the basics.
Coping with Corruption
As you'll know from general guides, Corrupted Blood is the gimmick mechanic of this encounter. Players want to avoid the many forms of "fire" in this fight, as all of it will cause your percentage of corruption to go up, which can eventually result in you turning into an unhealable, faceless monster if it gets to 100%.
Unfortunately, there isn't much you can do as a healer to reduce the amount of corruption your raid takes (since corruption is primarily caused by avoidable boss abilities), but you can help out in one tiny way. The second level of corruption, Corruption: Accelerated, is a debuff that will increase the rate at which an afflicted player receives corruption. Bad, right? Fortunately, Corruption: Accelerated is a dispellable magic debuff, so use Dispel Magic against it as quickly as possible. More and more players will end up with Corruption: Accelerated as a fight goes on, so make sure that this debuff is added to display on your raid frames. Also, Glyph of Dispel Magic comes in quite handy, especially in the second phase of the fight.
In phase 1 Cho'gall will constantly summon a fire or shadow elemental, consume its powers, and then perform a corresponding attack on your raid. When he uses Flame's Orders (fire), he'll attack your tank with powerful melee swings and place patches of fire on the ground. For Shadow's Orders (shadow), he'll attack your raid with three pulses of AoE shadow damage. Cho'gall will alternate between both these orders, but if you're not paying attention for a moment, forget things easily, or just want a quick visual reference, it's useful to set Cho'gall as your focus so you can see what buffs he has. (Good for Twisted Devotion, which we'll get to later.) You can also just look at the hammer he's holding, which will glow red or purple depending on which buff he's consumed.
You'll want to adjust your healing on this fight to match the output damage. Holy priests will find the duration of each buff is just right for them to switch between Chakra: Sanctuary and Chakra: Serenity. That means before the shadow attack, a holy priest might want to place Holy Word: Sanctuary, get some Serendipity stacks, and make sure the raid is topped off with Circle of Healing. For the fire attack, spam your single-target spells and use Holy Word: Serenity if you fall behind before the next melee swing.
Disc priests, on the other hand, can respond to the fiery tank damage with the usual arsenal of strong, single-target spells (Penance, Greater Heal, etc.). For Shadow's Orders, prepare for the AoE by casting Power Word: Shield on as many players as you have the mana for, then cast Prayer of Healing after the pulses begin. Power Word: Barrier can also be used, especially if Cho'gall has a stack of Twisted Devotion. Let's explain that now.
Conversion Cho'gall will periodically afflict members of your raid with Conversion, an ability that causes your allies to worship Cho'gall. If this goes on for too long, Cho'gall will gain Twisted Devotion, a buff that increases his damage. It is thus very important that Conversion-afflicted players be interrupted.
The best ability to interrupting these players is -- wait for it -- Psychic Scream. Psychic Scream is instant-cast and AoE, so you can hit all the afflicted players at once without targeting. So if you're a healing priest, don't be stubborn about helping out with the crowd control. You're the best person for the job! Just know that right after you've used it, your friends will immediately be broken free of Conversion, so dispel Psychic Scream off them quickly so they don't run into anything bad on the ground. Oh, and if it wasn't obvious, you'll probably want to add Conversion to your raid frame display so you can respond quickly with Psychic Scream.
There are also occasionally spawning adds in phase 1 called Corrupting Adherents. Priests should be mindful of this part of the fight in a couple of ways. First, when an add spawns and your off tank goes to pick it up, you'll immediately be splitting your healers between targets. If this happens to occur during Shadow's Orders, the healing will start to get stretched thin and you may want to consider using a cooldown like Guardian Spirit or Pain Suppression on whatever tank needs it most. (You can also reactively use these two cooldowns before Flame's Orders if Cho'gall has Twisted Devotion.)
Most of the raid damage is avoidable when the Adherent is present, but there is a chance that you'll have to do some raid healing if anyone stands in fire for too long. Additional raid damage can also occur if your tanks and DPS don't interrupt Depravity, one of the abilities the Adherents cast. Your normal approach to AoE healing will work just fine in these cases.
When an Adherent dies, he will always create a void zone under him that spawns miniature slime adds called Spilled Blood of the Old God. In addition to that, any existing void zones created earlier in the fight will also spawn miniature slime adds. So, to keep things orderly and make it easier to AoE down the slime adds, your raid will want to stack void zones on top of each other. That's where you can come in as a priest to help. A tank needs to kite the Adherent across the void zone as it dies in order to get the void zones stacked. A tank obviously can't run through the void zone, though, so depending on what abilities he has, you may end up using Leap of Faith to pull him across. Clever, huh?
One last thing to note is that when the Spilled Blood of the Old God does spawn, you will almost always aggro them as a healer. You don't want to get hit by these adds, so counter their threat by using Fade every time they spawn. This is important because sometimes they will die slower, particularly late in the fight when there a lot more of them appearing at a time.
Ideally, you'll go into phase 2 with a lot of mana so you can heal reactively to whatever your raid needs. This phase can be quite chaotic because corruption in your raid will start to increase since Cho'gall will be hitting the raid with Corruption of the Old Gods, a pulsing aura that damages and increases corruption. Remember that you'll need to stay on top of dispelling Corruption: Accelerated!
In this phase, Cho'gall will also summon Darkened Creations, which are eyestalks that will channel a 75% healing and damage reduction debuff on members of your raid. Killing these eyestalks is a priority, because your raid is not operating at 100% output until they're all down. For that reason, even healers should try to help out with damage. Smite your heart out if you're a disc priest with Archangel. If you're holy, do the same, but I don't recommend taking on Chakra: Chastise; there is plenty of healing to do, and you don't want to get behind being in the wrong stance.
Use cooldowns wisely
I already mentioned how to use Pain Suppression and Guardian Spirit, but that still leaves Shadowfiend, Hymn of Hope and Divine Hymn. For Shadowfiend, you can use the little guy whenever it's convenient for you. Once very early in the fight and then again later in the fight is probably going to be the best choice, since phase 2 is so mana-intensive.
You'll want to use Hymn of Hope sometime before phase 2 starts. I find the best time to use it is right after the three pulses of AoE shadow damage from Shadow's Orders. There is no urgency to heal the shadow damage once it's been dealt if everyone lived through it, so use the time immediately after to channel Hymn of Hope or a Potion of Concentration. I try to avoid using those abilities after Flame's Orders because while the shadow pulse will always be three ticks, the amount of times Cho'gall swings at your tank with additional damage will vary each cycle.
Divine Hymn (and its older brother, Tranquility) are best if saved for phase 2. You can use them after your raid has killed all the eyestalks and you need to get caught up on healing quickly.
Holy or discipline?
This is one of those fights you can go either way on as a priest. The blend of damage will keep either priest busy, and cooldowns each priest has are on par with each other. That said, holy priests are perfect on this fight because of their ability to swap between two healing "stances," so it may be one of those fights you want to try out as both and see what works better for you and your raid.
Questions? Concerns? Leave them in the comments. Also if you have any questions for future columns, I'll be getting into individual topics over the next week. If there is something you'd like me to cover, now is the time to let me know what.
You may also be interested in reading Priest healing strategies for early Bastion of Twilight and Priest healing Ascendant Council.
Spiritual Guidance has the inside line on pre-raid gear, valor point and raid gear, and healing strategies for bosses such as Atramedes and Chimaeron. Newcomer to the priest class? Look into Discipline Priest 101 and Holy Priest 101.