Apparently, there's a Vocaloid song called "Karakuri Pierrot". Any idea what to do with this information?

That was honestly the very first thing I thought when I heard ‘Karako’ before we even knew his Caste Name was Pierot- But Aysha confirmed that Karako comes from Karakoze, arabic for clown (Although it may be a dialect? It seems like Karakoze means more literally ‘someone in colorful/rainbow clothes’, so not quite sure). Either way, it’s likely a coincidence in that case.