Ryuma

Ryuma is one of the Immortals, and both an earthbending and firebending master. He is able to utilize both elements, as well as two techniques of both: lavabending and sunbending, respectively. Originally born into the Lava Realm, Ryuma is known to have fought in several battles, including at the New World, during the Riverlands Rebellion. An earthbender by birth, he later learned the art of firebending as well, mastering both to become a prodigy - as well as their sub-elements.

Trivia

 * His birthday is canonically stated to be in February.
 * Gram is his surname.