Phase 3: Prophet

Easy Solo for Level 70 Dragonflight, Level 80 Worldsoul Saga & Beyond...

1. Normal Difficulty.

2. Clear trash in boss room.

3. Head back out of boss room, take a right and head north and pull the Disciple of the Prophet all the way back to the boss room. Disciple Location is 60, 30 approx.

4. Once Disciple of the Prophet is in boss room, begin fight. Disciple splits into three Disciples of the Prophet.

5. Take them out.

6. Nuke boss down.

7. ?

8. Prophet. Achievement Completed.

There is an add the is far north on the right side of your map called the Disciple of the Prophet. Kite him into the boss room and damage him down to about 10% (ready to kill).

Pull the boss and hero. The add will split into 3. Kill the one add that is really low and start working on the other 2. Once they are dead you can finish the fight as normal.
Look at the screenshots to see where on the map the add is.

Easy solo in Dragonflight. Just pull the add all the way over to the boss room (60 30 ish on the map), pull the boss, kill the now 3 adds, kill boss, wait 5 seconds, get achievement. The illusion phase doesn't matter at all, you can kill the wrong one 6 times and not fall below 90% health.