from Under Observation: My First Loves and I
Hanna YOO was Jung-Hee's first love to show their backstory in the webtoon. She is a swimmer and often tried to teach Jung-Hee how to swim, soon realising that she just wanted to swim with him out of developing feelings for him.

Under Observation: My First Loves and I
Junhee's a pushover and has somehow managed to lend out all his money. He finally finds a great part-time gig, but it's only for women! In serious need of the cash, he dresses up as a girl only to discover the job he's just applied for is a clinical trial on a libido pill for women. Not only is he locked in for a week with five other (ahem, horny) women, they're all women from his high school! How long before everyone discovers he's not a she?