There are two parts to this fight. The first part takes place on the south side of the bridge and the second part on the north side of the bridge.
He will cast two abilities, one every 30 seconds. To prevent your raid from dying to them, you will need to kill books. Psychotic books block the Psychocontrapulation AE's at 30/90/150/210 etc, Astral books prevent the SuperMegaNova AE's at 60/120/180/240 etc. After killing a book, everyone within 10-15m of it's death will be immune for 10 seconds.
He will respawn all 4 books every 60 seconds regardless.
One strategy is to burn down one Astral/Psychotic immediately, then kill the second Psychotic around 20s, then the final book around 50s, just leaving everything stacked up.
If your raid lacks our DPS/gear, you can alternatively pull the books away from your raid because they do have some stacking AoE's themselves.
Rinse/repeat down to 50%.
At 50%, the mob will port just like old Fitz!
It will port to the other side where the Drake/Basilisk/Eyeball/Fitz will all activate. Have your most stout tank group grab Basilisk+Drake. Have another tank group grab Fitz, and have a third tank grab the eye. You must interrupt every ability the mobs use on this side. The AOE's hit very hard and you can survive if one or two go off but learn to interrupt each one. The basilisk has a VERY fast casting AOE so make sure you pay special attention with your interrupts on this mob.
Burn the eye. Then pull the Basilisk off the other group, and kill him. Finally, kill the drake. Then your raid kills Fitz.
Fitz will still need to be interrupted throughout all stages of the fight or he will ravage you with Discombobulate.