Cocytus

Having an enormous body size of 2.5m, Cocytus has the appearance of an insect walking on two feet, a fusion between a mantis and an ant.

With a tail twice as long as his height, Cocytus is covered with sharp spikes like icicles and has a strong jaw that can easily snap people's hands. Two of his hands hold a silver halberd, while the remaining two hands hold a mace emitting black light and a crooked shape sheath which seems to be for a broadsword. With a breathtaking cold air, the pale blue, hardened bone armor oozes out diamond dust like bright light. His shoulders and back look like an uplifted iceberg.

(Source: Overlord Wiki)