Avatar: Legend of Korra
Her "pet" is half-dog, half-polar bear. And I thought it's a boy, but she call it "her" and the name of this cross-breed animal is "Naga".
Her master "Tenzin" is the son of Aang and Katara, the only one left I guess. Korra trains airbending together with Tenzin's children. I'm glad that this Avatar doesn't get boring. So, any movie for this? hahaha