Bo Dragon

Bo Dragon is an extremely large dragon living inside the volcano Bo Mountain. When Bo Dragon is sick, he coughs volcanic ashes. He is temperamental, with it being said that it is impossible to make him laugh. Princess Lione has a bond with the dragon and can tell what he's thinking and feeling. When the twins were searching for the Grace Stones, they learned that the Bo Dragon possessed one, yet despite their best efforts, and those of Bright and Boomo, nobody was able to make the dragon laugh. Unexpectedly, Princess Altezza freaked out at having the pressure of making the dragon laugh all by herself, and unintentionally caused the gem to appear when she caused him to do so.

Trivia

 * The Bo Dragon does not appear in the manga, in its place is the Sky Dragon.