There 4 bosses in this dungeon and 3 out of 4 bosses have an achivement that needs to be ocmpleted if you want the red-proto drake.
The first boss is just an easy tank and spank boss. If you want the achievement here you need high dps. It is called <Consumption Junction>
The second boss is guarded by a shield and 4 adds while spawn (1 at a time). When the 4 adds come adds will also spawn from the stairs these adds should be picked up by 1 dps if no add leae the stairs you will get an achievement called <Oh Novos> When the shield breaks its just tank and spank and the tank needs to pick up the adds that he summon in him the adds have very low life.
The third boss is a giant raptor lookalike boss and also has one achievement on him. He walks in a den with raptors if you kill some raptors then boss you wont get an achievement. however if you aggro the boss and then kill 6 raptors found in the den he lives while hs alive and then kill the boss you wil get the achievement < better of dred>. He also spawns 2 raptors during the enounter with around 60k life and he also uses an atack at the tank which let the tank bleed and it can only be removed by fully heaing the one who got the debuff (the one who has the aggro)
The last boss is An skeleten wyvern type. He sometimes cast an AoE on the gorund you must not stand in that. Also after you killed around 150k He will cast decay flesh turning everyone in skeletons the tank should use the spell taunt. shield and life steal and the dps/healers should use attack and life steal.