Sentinel

Sentinels are a non-player character in the game brutal.io, one of two currently discovered by players. Sentinels spawn inside the room with a black hole at the red electrified things, and only when there are very few players remaining in a room, hence making them fairly rare. In English, a sentinel is a guard or object that exits to keep watch over and guard a valuable site/object. From this, we can infer their purpose is to protect the Red Flail so players in a sparsely populated room can't just go in and grab it without a challenge to win the game. Very little is known about the Sentinels, other than that they were recently added.

Sentinels are the same sprite as the unnamed green, fish-like NPCs that grant players very small amounts of energy and commonly spawn evenly throughout in the Map. However, they have the same color as the Car of a player with the Red Flail. On contact with the a Sentinel the player will be deleted. Around two Sentinels inhabit the Black Hole area at one time. Sentinels are able to leave the area. It is unknown how far they can stray from that area. Just like their green counterparts, they are deleted with one hit of your Flail and grant 1000 energy. However, they do not run away from you as you near. On contact with a Sentinel, you are given the message, "DELETED BY SENTINEL".