For me, it's just that overly serious all the time, and is quite happy to make disparaging remarks or two or just plain make fun of the main team. Where the others all take themselves way to seriously, but I suspect after centuries of only really fighting against other system lords and only really having servants to talk to, I think he enjoyed having having someone else in the arena to battle wits against.

I never heard that said before but it wouldn't surprise me which how the role evolved over the seasons.