[Crossover] The Protagonist's Sister, Mary Sue

The female lead is a goofy, chuuni, siscon Mary Sue. Hikaru Shindo: Sis, I want to become a professional Go player. Mary Sue: Go for it! Become the next Tom Sue, who can punch Meijin Toya and kick Honinbo Kuwabara! Hikaru Shindo: ...What the heck? Ryoma Echizen: I lost to Dad again... Mary Sue: So what! A handsome young man like Tezuka or Fuji is much better suited for you to win over than a scruffy old guy like your dad! Ryoma Echizen: ...Where's the logic? Ichigo Kurosaki: I have to rescue Rukia! Mary Sue: At the crucial moment, you should swish your cape, hold a girl in one arm, and defeat every boss with the other! Then every beauty will fall at your feet! Ichigo Kurosaki: ...Sis is going crazy again. Tsuna Sawada: I don't want to be a [redacted]! Help! Mary Sue: Don't worry, of course you won't be a [redacted]. As my little brother, you'll become the God of the New World, and every [redacted] will be your underling! Tsuna Sawada: ...TAT Sis, are you Byakuran's actual older sister? Yuki Cross: Sis, tell me a story! Mary Sue: Once upon a time, there was a goddess of a new world named Mary Sue. She was so beautiful she could topple nations, make fish forget to swim, make flowers bloom at the sight of her, and drive people to despair. Anyone who saw her fell in love with her... Kaname Kuran: ...That's right. You really do drive people to despair. Mary Sue: Don't fall in love with me. I'm a legend! Of course, if you do fall for me, I can't help it. I'm a devoted person, so I won't add you to my harem! Unless you cry, throw a tantrum, and threaten to hang yourself, then I'll consider it. Everyone: ...Well, thanks for that.