Initially, guarded and haughty; he is refined and quiet, but has a firm bark when he's going about business. He also has a bad case of resting bitch face. Despite this, he can be soft and kind when needed. His voice sounds like this, or this. He wears a white kariginu over a blue kimono with hakama tightened at the knee and sandals, giving him a somewhat Shinto aesthetic. Anyone in tune with spirits (especially ones of nature) will be able to sense he is not simply a mere boy, and he is older than he appears. He probably smells like fresh, crisp water or something clean.

Arcane Knowledge & Spellcasting: His spells include minor telekinesis, invisibility cloaking, force-field imprisonment, and relaying visual information mentally through touch; a lot of them seem to be related to subterfuge and defense, and nothing is ever widely devastating. He also knows a great deal of spiritual world lore as well as how to imbue food with magical properties.

Dragon Physiology: He can transform into his river spirit form: a blue and white Asian dragon. He can do your usual feisty draggy business in this form, including swiping claws, biting with his teeth, and hitting with his tail.

cantaloupe
cat ear headband
25 pound bag of rice
one foil of Poptarts