This guy is from royalty / a lord and he goes to work under a commander who HATES royalty. The commander falls in love quickly, realising it after he sees the royalty guy kissing his ‘fake’ boyfriend
https://www.mangago.me/read-manga/oh_captain_my_captain/ I think it's this but not 100%

this psychological manhwa that has an exchange student fall i for a bully victim and they share a love of radios in the first chapter or so. After that it turns out the saviour is a true psycho and the victim of bullying gets involved in busing evidence of killings and the two actually share a dark past and know each other from playing in the playground togethr