in short

they're just sporunes who had the bad luck of study performance and get hired as a jester for doomy or anything related to the purgatory and clown work thing

once this happen changes will happen like:

can survive of being decapitated complety, thought they need the head so the body would still ''alive'' even that and can reconnect the head

the considerable flexibility gain

and the most normal thing of those weirdos are the loss of sanity

some are no ironically used in battle and normally they only bring a explosive gift, normally killing themselves in the act