Ettin

The ettin is a form of two-headed giant from the Dungeons & Dragons roleplaying game. A primal and savage beast, yet each head is capable of independent thought and controls the arm and leg on its own side of the shared body. When facing a common threat, the two heads of the ettin will cooperate, but otherwise they frequently disagree and argue with one another.

Traits
The ettin serves as an exception to the rule of two heads being better than one; an ettin's heads each have their own thoughts and constantly disagree. Though not very smart, ettins are cunning fighters and are quite proficient with wielding two weapons at once.

Trivia
The name "ettin" is derived from an obsolete English cognate to the Old Norse Jötunn.