Lord Sasil

Strategy
To spawn him you must click on his coffing.

During the fight Sasil is invulnerable but will nonetheless attack you. Have your tank focus on keeping aggro on Sasil while the rest of the group kill the needed parts : There are 4 attackable coffins behind him. Kill the first one and kill the body part that comes out of it (a 84 solo skeleton named Sasil's head, or Sasil's chest etc will spawn). Repeat for second, third and forth coffin.

Sasil will then be vulnerable. Burn him down.