You may create one celestial without permission. Please ask Avalon to create a second+ celestial.
Celestials can be any creature or race or magical being.
Celestials are practically immortal unless they choose to die or are killed by another celestial. They have absolute power over all the elements and have all superhuman abilities, however they must train them selves and using their power costs energy. If they use to much energy, they can fall into a deep long sleep and even die.
The Celestial Gene isn't carried or passed down to offspring, it is given by choice of the cosmos. However there can only be 7 celestials alive at once time which is why celestials are mega-ultra rare. (If you want to create a celestial you can have them marked as deceased if 7 alive already exist.)