Love Comedy Manga ni Haitteshimatta node, Oshi no Make Heroine wo Zenryoku de Shiawase ni Suru

ラブコメ漫画に入ってしまったので、推しの負けヒロインを全力で幸せにする

In the world of a popular rom-com manga, my only mission as the friend of the MC is to make the losing heroine, Sei-chan, happy! "I'll definitely make you happy. Please go out with me." "W-Wait, what!? Y-You're being serious...?!" The manga adaptation of the sweet rom-com from Kakuyomu starts now! (Source: Kadokawa, translated)