Wererat

Wererat (人鼠) is a creature that inhabits the New World.

Appearance
Just as their name implied, it should have the appearance of some rat, but also considered as a variant-type like that of the werewolf.

Abilities
Like the Giant Rats, Wererats are even said to carry nasty diseases with them. In addition, it can resist damage made from everything except silver weapons.

Trivia

 * This is the second type of were-creature that appears in Overlord.