Gharj is in a lava pit, and also we don't have to worry about lava as it does very little damage.
First phase, is tank n spank. Once we see small isles come up from the lava, move to the next platform ( that is not shaking ). Every island is the same, except for third island. He enters frenzy like the previous ones, but this time spawns adds. AOE them down. Then proceed to next island. Its rinse n repeat from here on out!
1st Ability: Aoe front cone. DO not stand in front unless tank!
2nd ability: Pounce All melee get out of there! Does a nice amount of damage.