Ortakna, Lvl 33

To active Ortakna you need "Life Stone of Ortakna" and place on him to start fight. To obtain life stone you have to either defeat M'Karsa or using Special Portal Master to warp "Outer Corridor" by doing one of them life stone will be spawn at that location "see picture below". Ortakna is always VX mode.

Special Portal Master

Just by warping to M'Karsa you can spawn life stone w/o killing him.

Life Stone of Ortakna

Stone is spawn on that spot always.
Dark & Light Ortakna
Hands will be randomly cast on any spot of the ground upon entering the arena. After 3 seconds, the boss will start attacking players (use this time to deal damage and taunt him). When both Ortaknas' are killed, everyone will be teleported for the final fight with him. During the final phase, he hits faster and does much more damage so players should consider using smoke all the time.
Dark Ortakna
Dark Room/Phase
The tank should stay below the boss while healers should stay behind him. The rest of the players should surround the boss and deal damage while avoiding hands. Dark Phase Arena effect: -1.5 MPS.

Pillars/Runner Phase (Ortakna focuses all of his energy at -player name-)

Before random players are called, everyone must hug Ortakna and give space for the runner. After 8 seconds Ortakna starts attacking, the runner needs to pass behind glowed pillars a total of 4 times. The player will scatter many purple bullets from rears and whoever eats those will get heavily damaged. Each pillar glows once so you can more or less figure out the next glowing pillar.
PS: In some rare cases, the bottom-left pillar can glow 2 times. Whoever has aggro on the boss cannot be called. A viper will be spawn from the bottom between 2nd & 3rd glowing pillars, the tank needs to aggro, and killing this unit should be a priority for players. A few seconds later a portal will be opened on the top side of the room while Ortakna starts channeling arena wipe spell; everyone should enter that portal to avoid certain death.

Shadow Orb

After the second blinding light, a shadow orb will be spawned in a dark room and someone will need needs to go there to prevent the orb from reaching full hp and exploding. İf orb explodes, both arenas are affected and the outcome can be very lethal. More shadow orbs will be spawn if the fight takes longer. The second orb usually spawns in 1 min 25 sec.
Light Ortakna
Light Room/Phase
This portal doesn't close when people enter it, but it allows only one player to enter a dark room to prevent the shadow orb from exploding while dealing damage to Ortakna. Ortakna is inactive during the light phase so you shouldn't worry if you manage to steal an aggro (tank will have enough time to taunt the boss before it's too late). Light Phase Arena effect: -25 HPS.
Ball of Lights
These orbs randomly spawn on the arena and need to be killed by using AoE abilities. Each one explodes after approximately 8 seconds and each of them deals AoE damage and applies HPS reduction debuff (which depends on the game difficulty). You can avoid AoE explosions if you stay far enough but you cant prevent getting debuff. Normal: -4 HPS. Legendary: -5 HPS. Hardcore: -6 HPS. HPS debuff resets back to normal after returning from the dark room but restores again upon entering the light room.
-Player Name- becomes surrounded with blinding light!
A random player will be called (including tank), get stunned, and take damage while releasing a light path in 8 directions. Other players must avoid looking at a blinded player and avoid stepping in light paths (whoever looks at the player will get stunned and take damage). https://www.youtube.com/watch?v=O39e4XY2JtU
Ortakna begins to channel the "light beams..."
After the second blinding light, beams appear and start to spin clockwise/counterclockwise, while changing directions over time. Avoid getting hit by the beam not to take massive rapid damage. https://www.youtube.com/watch?v=yn_lTVWuaRQ After a while, the beams will disappear and the boss will start casting arena wipe spell, players will need to escape the arena by entering a newly opened portal.