Inside Plane of Tactics, you will find Vallon Zek. He is is located in the North Wing of the zone.
Before engaging, make sure to clear the trash mobs from the corners of his room.
Vallon Zek splits into 5 versions of himself once he hits a certain HP % (seems to be arund 60%). The key to this fight is that only 1 of these 5 splits is the “Real” Vallon Zek. Each time you kill the “Real” one, another wave of 5 Vallon’s will spawn and you will have to find and kill the “Real” one again. Repeat this process 4 of 5 times until you win (you’ll know because they’ll stop respawning and A Planar Projection spawn).
How do you find the “Real” Vallon Zek? Just setup a hotkey: /target Vallon_Zek00. The “Real” Vallon Zek always spawns first, so has 00 after his name. It also casts and runs faster than the rest of his phony friends.
There are two ways to handle the “fake” Vallon’s. You can have Knights and Rangers kite them around the room until the event is complete, or you can off tank them. The general strategy now days (2019) is to kite them around while the rest of the raid burns down the “Real” Vallon Zek spawns.
Adds do not despawn so once you have won the event, so you will still need to kill them all off afterwards.
Hail the A Planar Projection for your flag! Click on the door behind where Vallon Zek stands to port back to the zone in area.