Professor

Dr. Mizumi was of an unknown race. Link encountered a nearly drowned Rouru in a lake, and decided to bring him to Dr. Mizumi. Mizumi offered to let Rouru stay at his laboratory until he recovered. Soon after, though, Rouru had a fit, and destoyed most of the doctor's experiments and equipment. After Rouru was healed, he left with the rest of his flock and Link offered to help rebuild Mizumi's life work.

Dr. Mizumi also appeared in the Majora's Mask manga as a fisherman. He mistakes Link for the Zora, Mikau, since he is wearing the respective mask. Link gives him Lulu's egg for safe keeping and study.

Trivia
Dr. Mizumi's name is spelled with two "U'"s (Mizuumi) in the Majora's Mask manga.