oo i know what you mean! the first time i saw a green flag redhead is in Anti PT!!! i love it so much you should read it!!
Oh yeah I've read it you mean Hwi,! I loved him! I guess i should say it's only red haired guys who not the seme like Hwi, or uke, but if they are a side character than they are villains. But than agin non villain Mc are rare too, I can only think of Red Haired James, obviously from the title. Lol that's one you should read, but warning the back stories for both Mc are very fucked up and upsetting, there is some serious angst and drama, but there is plenty of light fluffy and funny parts to balance out the the bad ones, but has a very happy ending.
Oops I meant to say that Anti and RHJ are the only ones with green flag semes that I know of as well
You ever notice that red haired guys in bl are almost always villains? I can think of maybe one or two times they weren't because they were part of the couples but yeah many where they are villains. But as for the story it's nothing groundbreaking, but the uncensored smut is hot af.