When we killed him (real tibia), we entered the room equiping Sacred Tree Amulet.
Stay away from his UE because it deals a lot of damage and the boss will heal a lot if he hits more than 1 player.
Step by step:
1. Kill 4 Antenaes.
2. Attack Doctor Marrow. Only one player (EK) by his side. You will have to attack him until he disappears.
3. At the north of the room will Spawn a black creature, STAY AS FAR AS YOU CAN FROM IT, she will disappear.
4. Kill Munster: You will see it has 20 Charges.You have to decrease the charges to kill the boss so you have to kill the orange containers around the room, they will drop something orange on the floor and the Munster must walk through it so it charges will decrease.
5. While you are killing the orange containers and decresing Munster Charges, the rest of the team have to attack Munster.
NOTE: The charges will increase if you stop doing 4 step.