Nijiiro Days (MIZUNO Minami) Summary:
From Chibi Manga: There's Na-chan, who's bullying, and on the other side Mattsun who's popular. There's also Megumi-chan who's a sadist and Tsuyobon who's an anime otaku. And then those four are interweaving with both of their year and that's the beginning of silly and thrilling love stories. But on Christmas Eve, the heartbroken Nacchan met someone who has on a Santa uniform?!