|Masatoshi Yanaihara||Ao Yanaihara|
Aoko Yanaihara (柳井原 青子 Yanaihara Aoko) or Masatoshi (允俊 Masatoshi) is SHSL Toxicologist at the rebuilt Kibougamine Academy under the identity of Masatoshi Kuroba. He is a transgender male with highly regarded qualifications in several scientific fields.
- 1 - 3 Low - Average
- 4 - 6 Above Average - High
- 7 - 10 Extremely High - Perfect
- The name Aoko (青子) means 'blue child'.
- Yanaihara is written using the kanji for 'willow' (柳), 'well' (井) and 'field' (原)
- The last name 'Yanaihara' is a reference to the Japanese billionaire Tadashi Yanai as in Mainverse, the Yanaihara family owns the second-largest holding company in Japan and fifth in the world. According to Masatoshi, they fund groups that deal with exports to other countries and some trades with foreign companies. They are considered to be zaibatsu.
- Like Masatoshi, Aoko's blood type is A
- Aoko has the ability to recognise the taste and scent of any chemical he comes into contact with.
- Aoko's hobby is shikantaza.
- His favourite foods are anything crunchy, while his least favourite food is butajiro.
- He likes cold showers and hot baths, while he dislikes dark rooms and being alone.
- Aoko's most treasured item is life.