oh man. hi anon. i'm writing a whole essay on yodaka and his novel rn but yes !!! there'll be some mainsto and whatnot spoilers here!! yodaka and yunyun are coworkers not just at ten nights BAR, but in the past they were part of an organization similar to ten's. it's hinted that they may come from the future? anyw, yunyun's role in yodaka's story is to keep him from remembering his past since he suffers when he thinks about it. he's kind of a foil to shunin in that way as he's attempting to shield yodaka from harm and keep him in this comfortable unchanging stasis that he wants to stay in while shunin is attempting to drag him out of that stasis and move forward despite potential hurt and hard times. it's for this reason that we see him in the end of mainsto sabotaging l4mps live as he sees hama tours as something that will harm yodaka. he's also most likely stuck in yodaka's karmic reincarnation cycle and remembers everything from every life before their current one or at least a large majority of it. they're a crazy duo with a lot going on, i really hope yodaka is the l4mps feature and we get more expansion on his lore U_U