Group setup for beginners should contain 3 tanks (or 2 tanks and one plate dps with good tanking gear), 3 healers and 4 dps. I will use those tanks' names in this guide: Sarth Tank, Drake Tank, Adds Tank. Sarth Tank tanks Sartharion, Drake Tank tanks Tenebron and Adds Tank takes care about Fire Elementals and whelps.
Trash Fight
After you enter instance, go left and fight your way to the first drake, Vesperon. Kill him according to Easy mode tactics. Then go back to entrance and fight your way in opposite direction to Shadron. Kill him according to Easy mode tactics.
Tenebron Fight
Engage boss as shown on movie below. He should be tanked at south-east end of his platform. It leaves a lot of place for group and makes Lava Waves avoiding very easy.
Immediately after you engage Sartharion, whole raid will gain Power of Tenebron aura, which increases shadow damage taken by 100%.
30 seconds after engaging Sartharion, Tenebron will join the fight. Your Drake Tank should move to west side of platform to pick up Tenebron.
Tenebron summons portal after 15-20 seconds with eggs inside. You have two options there:
Ignore the portal and burn down Tenebron as fast as possible, while Adds Tank keeps Fire Elementals and whelps on him (I suppose you need regular tank for this, dps in plate won't survive).
2-3 highest dps take portal quickly and try to burn as many eggs as possible. You won't have time to AoE them all. You need to focus your dps to burn them one by one. It is better to kill just 3-4 eggs than AoE 15 eggs to 10% and run out of time. You don't need a healer inside portal.
Tenebron ability: Shadow breath
Frontal attack that deals quite a lot of shadow damage (because of Power of Tenebron aura). Drake Tank should keep Tenebron's breath away from rest of the group.
Tenebron ability: Shadow Fissure
Creates a shadowy area on the ground, which hits everyone inside after 5 seconds with large amount of shadow damage. It is often not visible due to Desecration and Death and Decay AoE threat abilities. Lowering spell details can help with spotting Shadow Fissure. Because of Power of Tenebron aura, this ability is very dangerous.
After you kill Tenebron, kill all remaining whelps and Fire Elementals. Keep in mind, that whelps can apply a stacking Fade Armor debuff, reducing armor by about 1200.
Sartharion Fight
Now you can start working on the boss. During whole fight, at certain intervals Sartharion will spawn 2-4 Fire Elementals that should be off-tanked by Adds Tank. At 10% Sartharion spawns additional 5-10 Fire Elementals. They have around 26k hp and hit for about 800 dmg. Off-tank job is to keep them off the group. AoE tank with strong AoE threat is preferred. AoE taunts are dangerous, because you can taunt Sartharion accidently. Key issue is moving with those adds to avoid Lava Waves. If Lava Wave hit Fire Elemental, he enrages and hits for 400% normal damage. Enraged Elemental becomes bigger and DPS should burn him down. Having 3 or more enraged Elementals on OT is too much strain for Healers.
Sartharion ability: Tail Whip
He stuns for 2 secs with Tail Whip and deals minor damage.
Sartharion ability: Frontal Fire Breath
10k damage, only tank should be in front of him.
Sartharion ability: Pyrobuffet
He casts this at anyone outside of his platform, which kills instantly. However, you can briefly dip in the lava to avoid Lava Wave and it won't trigger Pyrobuffet.
Sartharion ability: Lava Waves
At certain intervals, Lava Wave will spawn on south or north edge of the platform. Waves from the south side, have two gaps. Waves from the north side, have one gap. Everyone, including tank, should fit in that gap to avoid fire damage and dots from Lava Wave. It is very nicely shown in the movie below.
Note: This video is for all 3 drakes up. Nevertheless it is the best video I could find that explains positioning and shows where Tenebron lands.
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