Cheat Meal

During phase 1, arcane echoes adds will spawn during the Soak mechanic, you must keep 1 Alive. During intermission bring the add through the middle beam to make it gain a buff called forged echo. Once the boss reaches 25% he will enter phase 2, if at that point you don't have an Arcane Echo with the Forged echo buff, you need to wipe and try again. Once phase 2 starts, void orbs will spawn, drag the add through them to convert the add into a void forged echo then kill it.

Edit: worth noting that there are 2 intermissions as long as you don't push the boss under 25%

Video Guide on how to get all the Glory of the Omega Raider achievements: https://youtu.be/cAtUHEE79_Y

This achievement revolves around the [npc=241923] that spawns during the fight. You can safely kill of the first arcane echo that spawns, but keep the second one alive. The boss will eventually reach 100 energy and cast [spell=1227631] were he does the ritual and spawns the arcane beam in the middle. The tank holding the arcane echo needs to pull the add into the beam which will transform the add into a [spell=1244502]. Tank keep holding on to the add and players don’t damage the add just yet. During the final phase were the boss casts [spell=1233076] and starts pulling everyone into the void, wait for the [npc=242589] to spawn. Once they spawn the forged echo will transform once again into a [spell=1248816]. Now defeat the add BEFORE defeating the boss to get the achievement.

We (20ppl, all 705-710ilvl) killed the first echo and played with the second one. The echos gather energie after being forged and in the end killed out tank with 25mil hits (in the first try where we tried to use the first echo). also they have quite low life. Also make sure not to accidently kill the boss too fast (esp. in 2nd phase).