Svokai Moriz is not one of the sanest individuals in the cult. It probably started when he misunderstood Seanan’s silver regimen and took a few doses of mercury. He’s since started taking the proper dosage of silver instead, but his lack of focus has left him nicknamed Wild Eyes Kai. He also dyes his beard, though it’s probably just because Anram does and so Kai assumes that was what you were supposed to do. It’s widely considered that he’s received a gift of inhuman strength from Slaanesh, because even a space marine might be hard pressed to carry around as ridiculous of a load as Kai does in the form of, in his own words, “reloads for me flail, in case I runs out in the middles of a fight. It wouldn’t do, no, not at all.” That’s right he carries what is basically 4 cannon balls around in his backpack, and doesn’t seemed phased by it in the slightly. I did warn you he wasn’t all there.
Kai usually claims he aspires to be a spaceship pilot, but his aspirations aren’t entirely consistent, and he as at various times expressed plans to become a Daemon Princess, Defiler, Ork Nob or Motorcycle. While some of this is attributable to lack of sanity, the truth is most of his poor grasp on reality is probably due to his rampant drug use (even for a Slaaneshii cultist). If he has indeed received a boon it’s likely to actually be immunity to overdosing.