Hui Shu

Hui Shu is a teacher at Taru International Academy and the only member of staff who is a Taruan Merfolk. Hui Shu teaches Defence Against Magic and carefully writes his words to the students in the air, instead of speaking them. Hui Shu lost his ability to speak after having his tongue forceable removed in the The Second Armada.
Unknown to the administrators of the academy, tongueless Merfolk leak painful song that other merfolk can hear. Meili, the first half-Merfolk student admitted to the academy struggles in his classes.
Hui Shu is unable to reschedule Meili's classes, and realises that Bohai Hàn, the king of Taruan Merfolk, may expect Hui Shu to keep an eye on her.
Hui Shu has avoided the clan since his painful incident in order to protect them. He has been informed that his brother resides in the The Chalk and Cider, and that the school has a secret portal to lead to it. However, Hui Shu has not visited his brother and prefers to keep to himself.

Mental characteristics

Employment

Most teachers aren't aware of how or why Alice Monaghan chose to employ Hui Shu, but he has been able to conduct his job well and most of his students who put in the effort towards their grade will meet their expectations or beyond.