A nice guy but straight, he's pretty much stable up until halfway through the novel (the "ghost" arc) where he starts to become TOO much like the character he's in and it starts f*cking with him. It's hard to say he's in love with the ML while reading, it's more so at the end where he's so used to the ML, he cares about him. I'd say he loves the ML and accepts him.

He didn't want to finish the final world targeting the brother, and instead focused on our ML character and left the world.

A virus that comes after MC kept failing the first world, he's MC's (non-related?) younger brother. He pretty much infected all the target characters by turning them into the obsessed, possessive, and yandere gongs.

In the final world (alternative version of MC's real world), he's not the target, but now a person who didn't exist before which helped MC like a "what if" someone had helped him in his actual world and saved him from abuse. He comes back to the real world with the MC and his memories are given to the real world brother

The system is mean and very unhelpful, but he's not a very skilled system which meant he couldn't fix the bugs aka ML virus

He doesn't let the ML keep the memories of MC in previous worlds.

MC's system being an alternate universe version of him that's the total opposite: scum gong was a crazy reveal.

Their real life had a pe*ophile step-dad and a abusive mother. The mother committed su*cide.