Descension

"Amid excited whispers from the crowd, one of the bhidhesi began to glow, and its owner crouched over it expectantly. The glow grew in intensity until it was almost painful to the eye. Then abruptly, it was gone, and so was the crystalline form; in its place, sat a small Emerald dragon, calling plaintively." (Foresight, Chapter Seven)

Descension ceremonies are festive occasions when the dragons attain their physical form. After this point, their riders abilities become much more prominent.