Doppelganger

Biology
A Doppelganger is a nightmarish skeletal mounted rider. The cloaked rider glows a ghostly blue, with its skull and ribs disturbingly prominent. It moves like a phantom, phasing in and out of existence. It appears to be in multiple places at once, or none at all, making enemy attacks sometimes miss entirely.

The mount is blood-red, and its skin is ragged like a tattered cloak, revealing not flesh but a ghastly light.

A Doppelganger cuts enemies to ribbons by swinging its reaper scythe with supernatural speed. Often, by the time a foe can react, a Doppelganger has already landed several strikes.