When Avatar: The Last Airbenderpremieres on Feb. 22, its titular tween protagonist Aang (Gordon Cormier) will guide fans through a vast fantastical land. It’s a world of new cultures, as four nations populate the fantasy series: the Air Nomads, the Earth Kingdom, the Water Tribes, and the Fire Nation. And, it’s a world of new powers — namely bending.

Certain citizens of each nation can “bend” their corresponding element, or manipulate it in some way. So you can expect to see earthbenders dazzle with rocks and dirt, or firebenders ignite a blaze using nothing but their bare hands. Then there’s the once-in-a-generation Avatar, who has mastery over all four elements. In Avatar: The Last Airbender, that fated hero is Aang.

“The experience [of portraying bending] was just so fun. I would go home and practice nonstop,” Cormier told Netflix. “On set in between takes, I’d practice. On my breaks, I’d...