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A Battle Bear pushes a Siege Tower towards the walls of Gobwin Knob.

Proposed Canon

A Battle Bear is a non-flying, humanoid Unit capable of both siege operations, as well as basic melee with Infantry. Battle Bears are capable of throwing rocks, but otherwise are not shown wielding weapons or carrying other units. They are shown pushing siege towers on multiple occasions, showing their importance in logistics and siege warfare.

Speculation

Battle Bears may be a type of Cloth Golem.