This is a short guide on how to complete the "For the Alliance!" achievement at level 70. Note that the same tactics more than likely apply at lvl 80, but probably won't require near the amount of people that they do now.
Step 1: Raid Preparation
This achievement is typically done with 2 raid groups at the same time for several reasons:
1) Stability.
It's much harder for horde to unseat two decked out, coordinated raid groups than it is to simply pick off the healers in one group. While one group is busy focusing on killing the boss, the other is running interference on any horde that might try to disrupt the boss kill with things like fears, stuns, or cyclones on the tank (particularly nasty).
2) Brute Force
Right now all the bosses are considered level 83, and as such they hit quite hard and are in turn, quite hard to hit. Your hunters and rogues are going to be doing the bulk of the work dps-wise on the bosses, so make sure that they're dropping agro as often as possible as well as letting the tank get a pretty decent lead on threat before opening up. We ended up having rogues and hunters from both raid groups focus on the boss, regardless of which raid had tagged first.
Our raid compositions looked something like this:
Tanks: 4-5
Healers: 11-12
DPS: The rest of the spots. Be sure to bring tons of rogues and hunters if you can.
All our gear is Sunwell quality, but this can more than likely be done with a group of people in t5-t6, as long as you're coordinated. Expect big hits on your tanks. You'll also want to stack hit rating if you're a dps class, as the bosses are notoriously hard to hit.
3) Order
Setup an order before you go kill bosses for which guild gets the kill credit. You're going to have to kill each boss at least twice for both raid groups to finish off their achievement.
4) Awesomeness
The sight of 80+ bears is much more awesome than 40!
Step 2: Into the Fray
Some guilds might prefer the straight forward approach of bursting through the gates of a city, instilling fear into all the citizens and more than likely agroing a couple dozen guards. This strategy has several flaws, the most prominent of which is placing more enemies between you and your objective: the world leader. It also alerts both local and world defense channels, so the element of surprise is really lost. I recommend doing small summoning teams.
Each of the horde capitals have small, secluded spots near their leaders from which a small team can summon an full 40 man raid. You're free to pick your own, but I would suggest scouting them out on a horde alt so you know the layout of the buildings as well as any patrols that might interrupt your summoning. We had 3 man teams that we sneaked into the cities and had them logout in place for when we needed them. Then we simply laid out a plan for which cities would be attacked and in which order.
Note: The respawn timer on the older bosses (Sylvanas, Cairne, and Thrall) seems to be around 2 hours. I'd suggest killing one and moving to another city instead of waiting for a respawn.
The logistics of summoning 40 people can be a bit tricky, but we typically had a whole group of the raid drop group so we could invite both our summoning team and three warlocks from the other raid group. We summoned their locks first, they dropped group to start summoning their raid, and we summoned ours. Typically, we started with our warlocks first, a couple tanks second, a couple healers third, and then the rest of the raid. This was done in case a patrol we hadn't seen pathed by or some horde player wandered into our summoning zone.
Step 3: The Bosses
Thrall:
Thrall's chain lightning is really the only ability that you have to worry about, as it can kill some of your melee dps if you're not paying attention. All the tanks should be building threat on Thrall when not handling guards. This has the advantage of not only having the possibility of a backup tank taking control should the MT die, but also acting as a meat shield and absorbing the chain lightnings.
Logistically, Thrall can be quite tough mainly due to the number of people that frequent Orgrimmar on the horde side. Make sure that whichever raid isn't in charge of handling Thrall is taking care of the guards that spawn every 2-3 minutes as well as the horde that might come into the base.
Cairne:
Probably the hardest boss to tank because of his abilities. He frequently drops agro, so your dps is probably going to want to cool it for the first 20% or so. We had pretty much all but one of the tanks of both raid groups spamming taunt whenever it was off cooldown. The spare tank is on guard duty as well as an emergency tank for Cairne should he be pulled into the raid group after an Uppercut on the tanks.
Healers should be prepared to heal through some pretty massive damage on the tanks. Not only will he switch targets a lot due to tanks taunting, but he can also mortal strike and war stomp, which makes healing tanks that much harder. Be sure to pull Cairne off to one side of the tent and place all your ranged and healers on the other. He also has a cleave and a mild thunderclap (doesn't hit terribly hard).
Sylvanas:
Sylvanas is probably the hardest of all the bosses due to placement and who she's surrounded by. While we found a good summoning spot, this was our longest run to a boss, and we agroed a metric ton of guards. The strategy for the pull is to simply have both raid groups run in, but one of them stop at the doorway to Sylvanas's chamber to mop up the guards and Deathguard Elites. The other raid group dashes straight to Sylvanas and tags her as well as the other NPCs.
The two NPC's that need to be taken care of before The Dark Lady are Lyrlia Blackshield and Sarah Forthright. I would suggest tanks assigned to these and macros to pick them up quickly and pull them out of the raid. Not only do they do a nasty whirlwind, but they also do an intimidating shout, making them very big problems for the raid.
Once those two NPCs are taken care of, Lady Sylvanas is a pretty straightforward tank and spank fight. She will occasionally Vanish (and hopefully reappear, we had her bug out once) and reappear somewhere nearby. Marking her with a raid icon really helps with picking her back up. Hunters are free to pull agro on this fight, as she's quite content to sit at range and autoshot/multishot. Make sure that when she vanishes the hunters move so that they don't end up next to her. Her melee will one shot any non tank.
Note: We didn't have to deal with the huge problem that is Varimathras. We're pretty sure he's bugged out right now, but he wasn't attacking our raid.
Lor'themar Theron:
This guy can hit decently hard in melee, but is otherwise the easiest of the 4 leaders. He also has a few advisors with him that I recommend killing prior to taking down Lor'themar himself. Lor'themar's only ability worth mentioning is a Charm effect. I'm not sure what the cooldown is, but I was mind controlled several times by it, while our other tanks hardly saw any. I'm not positive, but it might also effect multiple targets.
Lor'themar is also the only boss, that we found anyway, with a short respawn timer. We managed to kill him 20 minutes after the other raid group got their first kill on him.
Step 4: Epix Time
There are no epics to enjoy. In fact, the bosses drop a measly 80 gold or so. However, you do have the benefit of not only crushing the spirit of the horde, but doing it in style with your new goggle equipped bear.
Feel free to ask questions. I also want to thank inthedrops for his help and advice!
To Do:
Pictures of our summoning spots.
