Of Germanic origin.
Oberyn is a variation of the name Oberon.
Oberon is the name that has been given to the outermost moon of the planet Uranus.
One famous Oberyn is fictional.
Oberyn Martell, from the kingdom of Westeros, is a character, portrayed for the TV by actor Pedro Pascal.
The character became widely known from the HBO’s TV series “Game of Thrones”, the adaptation of the fantasy novels “A Song of Ice and Fire” written by author George R.R. Martin.