I've watched recently 2 historical enemies/friends dramas, with good bromances, really good friendship, though they both are friends to enemies but not fully enemies, they are on opposite sides but still deeply care each other, relationships are on/off and interesting till the end: My Country: The New Age and Warrior Baek Dong Soo . in both dramas both guys are really good, in both SML would make you love more ))) (in Warrior SML is dark anti hero but ohh dear lord, I'm looking for character like him now, I'm in love )))
School 2013 is kind of modern/school version of that kind relationships as above 2 dramas. all 3 of them has VERY STRONG DEEP BROMANCE
also interesting story and also great SML/antihero (and star of the show) is in revenge drama Lucifer, in this story point is that they are enemies, they wont become friends but relationship develops and at the end there is very interesting understanding. it's good story, old but gold )))
also enemies to friends (though not that kind friends like in first 3 dramas, BFF-s and buddies) subject is in these dramas:
Remember: War of the Son
When the Devil Calls Your Name
Bad Guys
p.s. in first 2 romance is included but secondary subjects and friendship is main,
in lucifer and remember there is bit more romance (though also not romance centered) but good ones and good FLs
in school 2013, when the devil calls and "bad guys there is no romance.