The elderly Lake Scientist was first seen in Ocarina of Time, working in his laboratory perched on the edges of Lake Hylia. He is a researcher, using the lake's water with other chemical compounds to create potent medicines, such as eyedrops for Biggoron. In Majora's Mask, his alter-ego has set up a lab in Great Bay, and studies the marine organisms and climate. He also owns a carefully controlled water tank perfect for hatching Zora eggs!
In the Manga, he appears in one of the short stories and is referred to as Dr. Mizumi, though technically this is not considered to be canon, so I prefer to call him the Lake Scientist instead (as the Manga is less well known).
For the model itself, the body is quite easy because he doesn't have any legs and just a flat base to his robes. The head is more detailed though, especially around the mouth and eyes, so make sure you score the lines to get a neat shape. At many points in the construction you can use holes in the model to secure tabs from the inside, but finally closing the whole thing might be a bit tricky depending on what order you make it in.
Scaled to my other characters as usual, and stands about 17.7cm tall. Sounds small but remember he is very hunched over and actually has a large head.