How to reach boss arena
Kill Ghoul and walk into portal to summon Ultimate Guardian. He has all buffs you encountered in temple areas and same spell pool from other guardian statues. Main problem here is circle on the ground if you get caught you will get stunned like 10 second. Wearfor that.
Take "Glyph of Sun and Moon" from Throne to the left of the arena (you need to have a free slot in your "bag")
Tank starts to kite him by making very big circles while others stay in the middle. Grak creates dark particles from behind which damage on touching. Meanwhile he gains movement speed, attack-speed and +3k base attack damage.
Everyone gets "purge" skill animation on their feet, Krit (boss gets the same animation too) becomes invulnerable and chases a random player (can change his target) and does damage by staying close to you.
Starfall on every player, everyone should spread across the arena to prevent starfalls from stacking at same areas. By moving around most of the damage can be avoided.
Everyone should “Hold Position” after they position themselves. All move controls are reversed (Phase can start with either normal or as reversed controls). You can move by using target spells on player or aim the boss to get closer, "Feeling Dizzy Yet Fools!" notifies you that controls are changing each time. Boss casts mass purple orbs through his body and sends them randomly at a 360° angle. The tank should maintain max melee hit range to avoid getting hit by all of the orbs.
Spread and whoever got “Dark Screen” should press H, after dark is gone go away from that area because "Mini Grak" will appear at your spot to perform a instant death. "3 second later screen returns back to normal". If a player moves during the effect of the dark screen, will take rapid damage each mini step they attempt.
Again 5 seconds later a message "Grant me... your death!" will show up and Grak will perform same animation, and this time on all players will spawn (you must run away from that spot when you see the text) you will get hurt and stunned.
Tip: Put some distance from each other and smoke the boss in case healer gets dark (healer and tank have to stay close in case healer gets dark screen and still can heal the tank by using hero portraits).
The tank should go right to the entrance and slowly walk to the left side, as “!“ yellow marked lines appear on the ground 2/3 second later and the phoenix will shoot those marks. Touching the phoenix itself causes instant death but you can walk through fire lines: you will still take damage, but it's not lethal. Healers should stay close to the tank, ranged damage dealers can still dps but don't block tank & healers, give them some space.
All players should stick together to divide gained stacks among the team. “Fireball” bounces between players and gets "Solar Purification" total x30 and each stack you take more damage from that.
Sun appears on the left side, all damage dealers should focus on killing it, otherwise, twins will fully heal (in 20 seconds after the sun appears). Everyone takes damage during this phase, there are many flying fire bolts going towards the sun which deal damage on contact with players. Tank needs to be a bit more right side of arena to take less hit from fire bolts while healers can focus a bit more on DPS to keep them alive.
Grak completely turns into red and everyone starts to take damage, if not interrupted asap boss will kill everyone. For interrupt, Chaotic Knight “Chaotic Grasp” Y / Warrior “Charge” W / Phantom Stalker “Remorseless Strike” R / Paladin “Divine Touch” E / Bear “Maul” Q / Earthquaker "Heavy Strike" Q.
Called player gets caught by a yellow net, which immobilizes and damages a player. It should be killed ASAP to rescue the player from instant death in few seconds. (you cannot get the net if you play solo)