Heart is a tribe in Kumandra.
Raya resides in Heart, which is arguably Kumandra's most important location seeing as it houses the ancient Dragon Gem. Her father, Benja (Daniel Dae Kim), is the Chief of Heart and a sworn guardian of the powerful orb kept hidden in the land.
Chief Benja is the one who built the dragon bridge to connect Heart to the mainland in an attempt to join the five lands together. Once the bridge was finished being built, he invited the other lands to come for a banquet.
The tribe tends to wear blue and green colors to symbolize the importance of water. Coincidentally, Raya is forced to search for Sisu, the legendary water dragon, when the tribes break the Dragon Gem and awaken the Druun monsters.
Though Chief Benja turns to stone, he urges Raya to take a piece of the gem. Upon locating Sisu, the pair set out to repair the magic orb to bring back the Druun's victims, including Sisu's dragon siblings. Raya later reveals the first defeat of the Druun at the hands of Sisu and the other dragons occurred in Heart centuries before.
They kept the last remnants of dragon magic hidden away in the tribe of Heart.