The Side Character's Rise to Beloved White Moonlight: Quick Transmigration

World One, Western Fantasy: Villainess Heiress X Scheming Prince, complete Synopsis: She battles a transmigrated Mary Sue, stubbornly plays the role of a cool, clever woman who's deeply in love with the second male lead, and flirts with the male lead until he turns dark. Male lead at first: So I'm not the one she loves. That's actually good news. Later: She's a woman who can stand beside me. Still, it's a good thing I haven't fallen in love with her. Finally: I've laid the whole world at your feet. Can't you look at me once? World Two, Full-Dive Game: Cannon Fodder Player X Native Demon King Male lead at first: Who is she looking at through me? I really want to kill her. Later: I hate her tears. They make my heart beat again. Finally: Marry me and look only at me, and I'll spare that lowly bunch of humans. The male lead isn't split into multiple copies. He will lose his memory. One-on-one romance. Theme: For love and peace in the world