Overseer

Overseers are a type of demon.

Lore
Overseers are the large, brutish leaders of the Minions. Their main weapon is a barbed whip that they can use on their troops, throwing their subordinates into a bloodlust, or even causing the minion to mutate its form and charge against the nearest opponent. The Overseer can also create a healing vortex that seeks out damaged Minions, allowing them to regain lost life.

Diablo II
Overseers appear in of Diablo II.

Overseers use the following Skills: Cry Help (Attract), Healing Vortex, Minion Frenzy, Smite.

The first type of them is literally called Overseer and it spawns in Bloody Foothills on Nightmare and Hell. They lead Enslaved.

An Super-Unique Overseer is Shenk The Overseer.

All Overseer types have Immunity to Cold on.

Diablo Immortal
Overseers appear in Diablo Immortal.