Setting up and the pull
Having six healers is a good number for raids who are unfamiliar with the fight. As players gain more practice, Onyxia is doable with five healers. Any combination of healers will work. A Paladin or Shaman with Fire Resistance buffs will come in handy (but that can be any spec).
When pulling, hustle in with the tank. You'll want to send three healers to Ony's left and three healers to Ony's right. As Rossi found it, it's a very bad idea for the tank to escape the range of healers. Druids and Priests should have no problems on the pull if they can keep up with the tank running in.
In case you didn't get the hint, run in with the tank when they're pulling. The onus is on you to stay with them! If the tank gets Ony into position but dies because you're not in range, that is a healer position problem. There is no reason not to catch up with the tank since the tank and healers don't move much initially. You don't have to outrace him but you should be within 20-35 yards at least. Give him a bit of a lead-off and he should be fine.
It's hard to believe, but the pull is one of the dangerous components of the fight.
Oh, and park a Shaman with the group the tank is in.
Her Flame Breath (not to be confused with Deep Breath) and Wing Buffet will be the biggest threat. If anyone gets caught in a cleave, don't bother getting them back up.
This is the stage where no one should be sustaining any kind of damage. All healers will want to focus in on the main tank and apply as much HoTs as possible.
Expect 25kish-type hits from Onyxia on tanks who are sporting Ulduar level gear or higher.
- Priests: Keep Power Word: Shield up on every cool down. Extend that tank buffer as much as possible. Keep cycling Renew, Flash Heal, and Penance (if you have it).
- Shamans: Make sure there's an Earth Shield up. You can probably get away with Lesser Healing Wave spam here. But the choice is yours.
- Paladins: Sacred Shield on the tank at all times and maintain the Flash of Light HoT component. Beacon them in case you need to switch off to cover someone who happened to pull whelps. If that happens, you'll have other larger problems however.
- Druids: HoT up the tank with your Rejuvenation and Regrowth. Not much more I can add than that really.
Here's a case study of a pickup Onyxia that I participated in. This is a death log of one the melee DPS. This isn't a death log of the tank who died. But let's assume it is. Do not let four seconds of time go by without an actual healing spell landing. Keep dropping heals on your tank and do not be complacent.
Side note: The addon is called Obituary. Very handy for troubleshooting deaths. Recount works as well.
Standby for incoming whelp spawns. Your DPS should be able to handle them fairly easy. The raid isn't going to be taking a lot of damage at this point.
So why not have some fun?
Of course, if anyone comes in danger you should stop what you're doing and get them back into the green.
You'll also wish to send one or two healers to the entrance to heal the tank who is picking up incoming Dragonkin guards. Heal at range and stay away from the guards as much as possible.
Fireball damage should easily be manageable and should not pose a threat unless the entire raid is standing on top of each other. Have the raid do themselves a favor and spread out around the room.
Keep an eye on her or keep an ear open for your raid leader for the dreaded "DEEP BREATH" call. When you see or hear it, make a beeline for the side of the room and get out of the way of her breath (someone give her some mints).
This phase is just about identical to phase one. Priests will wish to rotate Fear Ward on the tanks. If your raid is blessed with the company of a Shaman, have them drop Tremor totem. You did place them in the tank group like I suggested earlier right?
No matter the case, simply keep rolling as much HoTs and shields as you can on your tank. The worse thing that can happen at this stage is if the tank gets gibbed while all the healers are scrambling around from being feared due to Onyxia's Bellowing Roar.
One last thing: Keep an eye on the ground. Specifically, stay away from the cracks on the floor. Eruptions will hurt but it shouldn't be anything you guys can't handle if you get hit by one from fear.
Want some more advice for working with the healers in your guild? Raid Rx has you covered with all there is to know! Looking for less healer-centric raiding advice? Take a look at our raiding column Ready Check.