Okay so SPOILER ALERT
Garon was in love with the Mc from the beginning and he loves him. The thing is when the Mc confronted him about his mom Garon said that he doesn't remember but he swears that he would never kill someone again and he apologized. And they will find the antidote to Garon will heal. And the thing that messed me up and made me drop it is after all those sacrifices hyuljoli (the brother/second ml) the Mc ends up choosing Garon. So yeah.

Listen I think Garon is the same kind as the bottom and he killed his mom with his poison.