Yasuki is very stoic, expressing little emotion and performing his tasks diligently. He is very protective of Mimane.
When Akito and Arumi Ashimine first entered Mayoiga, Yasuki fired arrows at them on site. Arumi was able use her powers to predict his shots helping Akito avoid his attacks. Their fight was interrupted by Mimane Miyou who excitedly and curiously approached the newcomers.
Akito and Arumi were introduced to Tanmen and the other members of Mayoiga. Tanmen apologized on Yasuki's behalf but when told to apologize himself, Yasuki remained silent. Yasuki would later apologize to Akito, stating Mimane getting too excited about the outside world whenever newcomers arrive as his reason.