He will call for secondary colors , like "orange", after a while & become immune. You need to bring the mob to the 2 colors that make orange (hint : red & yellow) and his immune buff will fade after a while. When it does, 2 adds will spawn & you can dps it again.
There is a puzzle involving the blocks to fill the chamber with water, no solution here so far.
( 4 gates, 4 plates by the gates, look at the picture above the gate the red symbol. count the red shapes ( sometimes all the shapes some times just the center ones ). on top of each block you will find red dots. if the picture has 7 red shapes then put a block with 7 dots on it onto the plate, if the picture has 24 red shapes on it then put multi blocks adding up to 24 on the plate. when you get it right you will hear and see a change to the gate. Do this for all 4 gates
Once the named is pulled a LARGE bubble will form. Drag the named into the large bubble. About every 25% the bubble will pop and a new bubble will form (I believe it was in a clockwise order). Move to the next bubble, rinse, and repeat.