All of 3-A has had their bloodtype referenced in the manga and all of them follow this trope really closely. (WordOfGod says he likes this trope.)

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||Negi Springfield|| AB ||
||Asuna Kagurazaka|| B ||
||Nodoka Miyazaki|| O ||
||Setsuna Sakurazaki|| A ||
||Konoka Konoe|| AB ||
||Chisame Hasegawa|| B ||
||Makie Sasaki|| O ||
||Sakurako Shiina|| B ||
||Satomi Hakase|| B ||
||Yue Ayase|| AB ||
||Kaede Nagase|| O ||
||Haruna Saotome|| B ||
||Ku Fei|| A ||
||Kazumi Asakura|| O ||
||Anna Yurievna Cocolova|| A ||
||Chao Lingshen|| O ||
||Mana Tatsumiya|| A ||
||Misora Kasuga|| A ||
||Satomi Hakase|| B ||
||Satsuki Yotsuba|| A ||
||Zazie Rainyday|| B ||
||Ako Izumi|| A ||
||Natsumi Murakami|| A ||
||Yuna Akashi|| A ||
||Akira Okochi|| AB ||
||Ayaka Yukihiro|| O ||
||Chizuru Naba|| A ||
||Fuka Narutaki|| A ||
||Fumika Narutaki|| A ||
||Misa Kakizaki|| O ||
||Madoka Kugimiya|| AB ||
||Evangeline [=McDowell=]|| Unknown ||[[note]]She is a vampire[[/note]]
||Sayo Aisaka|| N/A ||[[note]]She is a ghost[[/note]]
||Chachamaru Karakuri|| N/A ||[[note]]As a robot, she uses oil[[/note]]