Health:

• 10 Man: 4.8M
• 25 Man: 24M

Abilities: Phase 1 (tauntable):

• Flame Breath - 2 sec cast, 45 yard frontal cone, 20K unresisted.
• Cleave - 100% weapon damage frontal cone
• Wing Buffet - 15K damage 20 yard frontal cone, ignores armor
• Tail Sweep - 5K knocback near her tail, large knockback directly into whelps

Phase 2 (65%, no aggro):

• Fireball - 2 second cast, random target, 5K damage in a 10 yard aoe.
• Breath - Onyxia takes a deep breath... 6 seconds later, everything in front of her will take 4-5K damage per tick.   The closer in the middle of the breath, the more ticks, and likely fatal.
• Spawn Onyxian Whelps - 40 Whelps spawn, 20 from each side, 60K hp.
• Spawn Onyxian Warder - Spawns every 30 seconds, 190K hp, Ignite Weapon to current target, does 25K damage.   Blast Waves for 25K around him.

Phase 3 (40%, aggro reset):

• Bellowing Roar - 1.5 sec cast, 100 yard aoe fear for 3 seconds
• Eruption - 5K damage from lava cracks on the floor
• Spawn Onyxian Whelps - Whelps will continue to come, smaller numbers though

The Fight:

It's basically the same thing as the level 60 version, for all those old enough to have been there!

Phase 1:

Tauntable, tank her against the back wall.   People stay away from the front, cleaves, frontal cones, etc.   People stay away from the back or you'll find yourselves in the whelp caves.

DPS burn down until 65%

Phase 2:

No aggro, random target Fireballs.   Melee can still attack her from underneath the hit box.

40 whelps will spawn, 20 from either side.   HANDLE IT!    They hit for shit on tanks, about 500 damage, so I guess aoe them down.

This part is new though, every 30 seconds an Onyxia Warder will appear.   You remember those right, like one of them respawning midfight and someone going back there and aggro'ing and they come in and rape the raid.     Well, now it's part of the fight!    Anyways, looks like melee gonna hurt bad if they try to take them on, tank and range kill them.    Unless that 25K blast wave is survivable or something.

Anyways, last thing is when you see the emote "Onyxia takes a deep breath..."    You gotta run out of the way.   She'll point in some direction and everything in that line will take 4-5K per tick fire damage, more ticks in the middle, fatal death in the middle.    Best bet is to scatter to the sides to avoid it.

Repeat until 40%.

Phase 3:

Just like Phase 1, but aggro has reset.   So this is the hard part, dps gotta back off until the tank gets it again.   Yes this means you!

She also does an aoe fear every so often.   Go go tremors and wards.    She'll actually start a fear off right as she lands, so you might want to Fear Ward your tank for that moment, or something.

Also, during the fear, the lava cracks will shoot fire up doing 5K damage each time you're feared across one.   Well it's a 3 second fear, so should be survivable if you're topped off before fears.

Whelps will continue to spawn, not 20 at a time, just small trickles in, so HANDLE IT!

That's all folks, phase 1 mechanics apply so stay away from front and back and dps her to dead.