I snooped a little on 19 Days when I first saw Jian Yi, it seems a slice of life series, yea? Shishi's from Yu Yu Hakusho so like lol as shounen as it gets, but even tho he's a fighter, he's a kinda stylish, glamorous guy, so he's keener on more "normal" things like nightlife and shopping and shit than probs others in his series, so could be pretty flexible there tbh! I think what attracted me to Jian Yi is his high energy. Shishi is a fairly minor character but he seems to get on well with more flamboyant, vivacious, effervescent people. And Jian Yi gave me those vibes, idk! Made me curious.

Also I just love this art style and his character design and it caught my eye aesthetically haha. But could be similar reasoning IC too ngl! Shishi's a super vain person tho so he'd def be more inclined to talk to Jian Yi just cuz he's cute too hahah