See how often they participate in the script: HERE.
Character Story: A Doctor located in Castle Town, he helps Ilia after she is attacked by monsters. He is hesitant to help Link with the excuse of a busy schedule, but he responds well at the threat of Telma’s involvement.
Race Story: Humans typically live peacefully with other races throughout all of Hyrule. The more specific Hylian race is a subcategory of humans. They can be differentiated by their ears -- Humans have rounded ears and Hylians have pointed ears.