Grenth

Grenth is the god of death and cold. He is the patron god of Ritualists, Necromancers, Assassins, and Hydromancers and the lord of the Underworld.

This inscription can be found on the Statue of Grenth:

Grenth is the darkest of the Gods, and depicts his dark image with great efficiency. Although his body is that of human, he bears the skull of a fallen beast. Grenth, is often seen with minions crawling for his acceptance, for his followers are usually fanatic in his teachings.

Grenth wasn't always the god of death. The previous death god was Dhuum, but Grenth destroyed his tower and killed him and took control over the Underworld.