I'm assuming you're asking about 'You're My Loveprize', which, full disclosure, I'm pretty sure is a fan translation title for a Japanese BL (boys' love) visual novel. The official localized title might be different, but let's go with that. The main character is totally Hikaru Aiba, a high school guy who gets kind of roped into this strange 'prize' situation by a rich classmate. He's your classic 'ordinary guy thrust into weirdness' protagonist, which works for the self-insert vibe of these games. The other central character is the guy who 'wins' him, whose name honestly slips my mind—maybe Ryou? The dynamic is very much a power imbalance thing at the start, which is a staple of the genre.
But honestly, the supporting cast is what makes it memorable for me. There's Hikaru's best friend, who provides the comic relief and a bit of normalcy, and then usually a rival character or two who stir up drama and make the 'prize' winner jealous. The story spends a lot of time on Hikaru's internal monologue, his confusion, and his slow realization of his feelings, which feels authentic to a teenage perspective. The other guy, the pursuer, often comes off as arrogant at first, but you get his POV chapters later that soften him.
If you're new to these kinds of stories, the premise can seem really out there. It’s all about the emotional rollercoaster of the main pairing, with a lot of focus on forced proximity turning into genuine affection. The side characters mainly exist to push that along or offer alternative romantic tensions that never really go anywhere. I’d say Hikaru and his 'owner' are the undeniable core, with everyone else orbiting their messy relationship.