He was first mentioned by Vex when he described the extermination of his race at the hands of The Una Mens. The child Vex watched his father and the rest of his family starve to death as a result of having their hands cut off and not being able to feed.
Trick talked to Vex about Clust over a drink. Trick described him as a hero and a good man who was one of his best generals in The Great War. This surprised Vex who only knew of his father as a brute; with Trick explaining that the persecution against the Mesmers had left Clust bitter and broken.
When Vex started to leave, Trick told him he could see a lot of his father in him and that he may still have the chance to live up to his father's legacy.
Clust was talked about, but not seen (even as a portrait), and we do not know what he looked like.
- 4.11 End of a Line (mentioned only)