I think you are talking about the 2nd to last named that has two adds that are with it Sloth and Greed I think... You need to pull the named to the bottom of the steps and burn the two adds as fast as possible, by the time they die, the "Essence of x" will start spawning at the back of the room and slowly coming to the front. You absolutely must have an OT to pick these up before they reach the MT group which will be burning the named (because if they get close to the named you will likely wipe). When the "Essence of x" dies a pillar will spawn and give a buff to the person closest to it which will allow them to practically one shot the next "Essence of x" that spawns. They basically rinse and repeat this process until the named is killed and you loot the chest. There is a curse that has to be cured, so you cure it... The buff from the pillar is supposed to be a curse as well but I've never seen it come up as one, so have the people healing the OT group be careful about curing curses that come up after the death of an "Essence of x." There is no curse that cannot be cured or it will wipe the raid.
IF you are talking about the final boss it is a simple turn and burn so I don't know what you're talking about. Just make sure the OT grabs all of the statues and holds them until the end of the fight. The MT should easily be able to hold the grey adds and you cannot kill them anyhow, so yeah, focus the named down.