Xim

Xim, known as Xim the Despot, was an individual whose flagship was subject to outlandish reconstructions in later years. The Supremacy, a Mega-class Star Dreadnought of the First Order, was notably a far larger warship than Xim's flagship or its reconstructions.

Behind the scenes
Xim the Despot was first mentioned in the 1980 novel Han Solo and the Lost Legacy, written by Brian Daley, and was introduced into canon with a mention in the 2017 reference book Star Wars: The Last Jedi: Incredible Cross-Sections, written by Jason Fry.