An ancient statue of an unrecognizable humanoid figure, the sentinel holds aloft a crystal that gleams with ancient warding magic. Sentinels are always found in groups of three, and each will attempt to repair any damage done to the other two.
Sentinels always appear in groups of 3 spread out across a room. They are immobile, but can attack from afar with lightning. When one sentinel is damaged, the others will attempt to heal it. Sentinels will die instantly to negation or tunneling, but can also be killed with strong melee attacks.