>>3778208Shut the fuck up TVtropes, the majority of the time the "lancer" is competing with the MC for the primary love interest. For instance, Kain wants to win Rosa from Cecil and is lured into DARKNESS to do so, until he wises up.
Also, for explicitly gay/bi characters, it is generally the reformed villain who is an option for the MC, like how in Persona 2:IS you have the option of dicking down Jun once he stops being Joka-sama. Or more recently, the totally not friendship between Rean and Crow in Kiseki (which was so totally not gay they had Crow as one of the options alongside "canon" [blech] girl Alisa and fan favorite girl Altina [yay!] in the VR dating game).