Moziel
For harem: I'm ambivalent more thoughts below For Romance: It depends on how you want the MC's character development to go, will he begrudgingly become a hero as he forms connections with the good guys or will he be more of an antagonist/villain like character? If the former sure go for it could be interesting although this is more vanilla, if the latter then still maybe go for it if that's the story you want to tell however it's important to write this right because stories where female hero's hook up with a villain MC and just loses their personality and morals are really boring and kind of pointless.