Arche will do his absolute utmost to help! Probably with some amount of cranky admonishment/grumbling that unidentified undead ichor does not like to come out of fabric and he wishes the locals could stick to good old-fashioned bloodstains. Honestly Wangji being quiet would suit this little asshole just fine, they might even unexpectedly get along -- Arche would certainly have a lot of respect for his sword skills.