Hoshkar is a fun fight or could be considered too easy.
When you approach his lair you will notice he is surrounded by lava but there is a floating rock platform circling him. If your raid jumps on the rock you will notice a message on the screen saying the you feel an aura of protection around you.
For this fight, you need to have almost all your raid force standing on this little rock and your MT on the outer edge of Hoshkar's island keeping pace with the moving rock. If Hoshkar is on the island with you, you will not be able to damage him. If you place your raid off the rock he will do some massive AOE's and kill your raid. The rock saves your raid.
Keep your tank near the rock and keep pace, only allow 2 or 3 of your melee dps to get off the rock and behind Hoshkar (they will be ok from the AOE actually).
Keep going in circles until Hoshkar is dead. Nothing overly special about this mob.