Obsidian Sanctum Guide
Trash Mobs and the 3 Drake Lieutenants
While there is not much trash inside the Obsidian Sanctum the trash can easily wipe even an over geared raid group who are not prepared. There are 2 types of add packs inside the Sanctum: a pack of 4 dragons, and a pack with 2 Onyx Sanctum Guardians. The Guardians require a tank on teach and are a hard hitting tank and spank. They cast a Curse of Mending on random raid members which will heal them every time that player attacks. This needs to be dispelled or the targeted player needs to stop DPS till it wears off. The pack of four consists of an Onyx Brood General who when killed will break all CC from the other dragon kin and prevent them from being Cced again for the rest of the fight, 1-2 Onyx Flight Captains who have no major abilities but tend to hit very hard, and 1-2 Onyx Blaze Mistresses which should be killed first as they conjure up Flame Orbs that do damage to anyone near it.
All three drakes are very similar fights with small differences. All three drakes have a Shadow Breath so no one except the tank should be in front of them, all three will spawn void zones that should be avoided by all players, and each drake will spawn portals throughout the fight that can be taken by the raiders. While in a portal everyone will take shadow damage, and what you do in the portal depends on the drake you are facing. Depending on the drake you are facing it is currently acceptable to skip some of these portals.
Tenebron - located on the terrace to Sartharion’s right side, she will open portals into the Twilight realm that give players a chance to destroy her eggs. Left untouched these eggs will eventually spawn Twilight Whelps which will attack the raid. Currently it is much easier for players to ignore her portals and focus on DPSing her down while an off tank picks up her adds. Unless killed before engaging Sartharion, she will be called to aid him after 30 seconds, strengthening Sartharion even more.
Shadron - located on the terrace to the rear of Sartharion, Shadron will regularly open portals to the Twilight realm that will give players the opportunity to slay acolytes which Shadron will summon. Players will need to take these portals as the acolytes will give Shadron the Gift of Twilight which decreases Shadron’s suffered damage to zero. Send in an off tank, all your DPS, and a few healers (or just one on 10-man) and the acolyte will easily go down. Unless killed before engaging Sartharion, he will be called to aid him after 75 seconds, strengthening Sartharion even more.
While being an old fight Sartharion still requires the raid to have moderate movement skills and situational awareness, especially when attempting 3 drakes. Sartharion is most frequently done with no drakes alive, or all three drakes. While 1 or 2 drakes can also be done it seems almost silly not to just do all 3 and get the whole shebang out of the way.
Sartharion has all the abilities you would expect from a dragon: tail whip, a frontal Cleave, and a cone fire breath. Keeping Sartharion faced away from the raid with his tail out of the way is key here. The best spot I have personally found for the tank to stand is on the eastern tip of the island. That way Sartharion faces out toward the lava, his tail is towards the lava on the other side, and the DPS can spread out along his side while the tank can avoid the Lava Wave with just a few steps.
Sartharion has several unique abilities that make the fight a little bit more difficult, and fun. Throughout the fight Sartharion will summon Fire Elementals. They do not hit hard initially and should be picked up by an off tank. However if they are not killed and they manage to hit a Lava Wave they will enrage, gain more health and hit very hard. Killing the Fire Elementals at regular intervals and having your off tank drag them out of the Flame Waves is key. Lava waves will also be summoned throughout the fight. You will receive an emote about the wave, and then a wall of lava will sweep over the island. The waves can either move left to right or right to left. Each wave will have a safe spot that players will need to get to. If the wave moves left to right (looking in from the entrance of the room) there will be two openings on each end of the Lava Wave. If the wave sweeps right to left there will only be one opening in the center.
Between avoiding Lava Walls, and killing Fire Elementals all DPS should be on Sartharion. Getting up as many DoTs as possible makes this fight go much faster. Avoid the Lava Waves, kill off the Fire Elementals regularly, and keep Sartharion from turning to the raid and you will easily win this boss fight.
Doing Sartharion with three drakes up means he will continue to do all his normal abilities discussed above plus the drakes will now join the fight in intervals, buffing Sartharion and debuffing the raid. Void Zones will now appear throughout the fight and will one shot a player and should be avoided at all costs. The most viable tank for this fight is a Death Knight as they have the most cool downs. A priest healing the main tank is also a good idea as they can lend their wings or pain suppression as extra cool downs for the tank.
While most the loot available in the Obsidian Sanctum is outdated there are still a few noteworthy pieces, including some cool mounts.
Reins of the Black Drake - 3 Drake Only
Title: <Name> of the Nightfall - 3 Drake Only
Fury of the Five Flights - Amazing DPS trinket that will probably not be replaced until your guild reaches ToC 25 man.
Illustration of the Dragon Soul - Great trinket for caster DPS and healers a like
Reins of the Twilight Drake - 3 Drake Kill Only
Title: Twilight Vanquisher <Name> - 3 Drake Only
Besting the Black Dragonflight (10 & 25) - Simply defeat Sartharion normally to gain this achievement.
Gonna Go When the Volcano Blows (10 & 25) - This achievement requires the player to not be hit by Lava Strike during the fight. Not an achievement that your entire raid will get at once. Keep an eye on the sky and try to anticipate the spot where the meteor will drop. Also never stand in the same spot for more than a few seconds. When the raid comes together to dodge Lava Waves take a spot in the back away from everyone else. Around 10% Sarth will incite a meteor shower of sorts for around 5 seconds, try to move further away from him and concentrate on dodging the meteors until the shower is over. There is a good chance you will get this achievement by sheer luck. I would not suggest doing this achievement while leaving the drakes alive.
Less Is More (10 & 25) - Requires your raid to defeat Sartharion and the Twilight Drakes with fewer than 9 raid members or fewer than 21 players on 25 man. This achievement is easily done by a well geared group. Dropping DPS instead of healers or tanks is advised. Simply take out all the drakes, and then move on to Sartharion and kill him with your normal strategy and this achievement is yours.
The Twilight Zone (10 & 25) - Requires your raid to kill Sartharion while all three Twilight Drakes are still alive. Considered one of the hardest fights in the game this achievement may take awhile to get while using a normal strategy. But keep your cool and keep trying and it will be yours. Or use the zerg method and make it that much easier.