Gotrut is a disgusting visage of what the chaos gods' corruption can do to a man. His belly is fat and bloated, and his voice is heavy and hindered by lisps, facial rashes, mumps and all kinds of diseases and maladies that could stop one from speaking properly. As a devoted of nurgle, we hope to see a gleefull zeal with which the character spreads plague and disease among the 'lucky' victims of Gotrut's raids. Did we mention he's also a pirate?

Reference: https://www.youtube.com/watch?v=t8RFuHy_5SE (Khu'gath, a daemon of the god Gotrut worships)