Roku's waterbending master

Roku's waterbending teacher was an individual who instructed Avatar Roku in the art of waterbending when the Avatar was in the process of mastering the four elements.

History
Roku's waterbending teacher was a citizen of the Northern Water Tribe when Roku was a young man. He was a very skilled and powerful waterbender, as he demonstrated great proficiency in the art, eventually earning the title of waterbending master. Later in life, he was given the honor of teaching the Avatar.

At first, Roku experienced difficulties with learning waterbending, as it was the element opposite his native element, fire. However, after several years, Roku mastered the element, even being able to defeat his instructor in a duel.

Trivia

 * A more detailed look at Roku's master highlights a largely physical resemblance to Avatar Kuruk, specifically the beard and the size of the amulet around his neck.