Celestian (seh-LES-tee-an), the Star Wanderer, is said to be brother to Fharlanghn, the endless wanderer of the Prime Material. Celestian wanders the Astral, Ethereal and Inner Planes, especially the Astral. He is depicted as a tall, lean man of middle years, ebony-skinned and dark of eye. His garments are inky black, but somewhere about him he has his symbol of seven "stars" (gems) which blaze with the colors of far suns. The gems in his holy symbol are ruby, jacinth, topaz, emerald, sapphire, amethyst, and diamond. He has many unique spells unknown to other Powers (save perhaps Boccob). He affects meteors, comets, and similar heavenly bodies. As a form of Sky God, Celestian has influence over some aspects of light and weather.

The distant stars are an inspiration to travel; be encouraged to wander far from home, just as the stars do. The stars are eternal and are pleased to be a guide for both legs of a journey. The stars may reveal their secrets if you study them.

His worship is confined to a few sages, savants, and like souls, who often worship him privately or through travel to unknown lands and acquisition of knowledge. Celestian is a favored Power of good-aligned members of evil, nonhuman races; while their eyes are unable to tolerate daylight, they find acceptance and hope in the light of the stars.

The clerics of Celestian are divided into seven orders of ascending knowledge and power, bearing no special titles other than the number of their order; each order's holy symbol differs in which gem is placed at the center. This small clergy is very studious and meditative, and is also somewhat secretive and detached from everyday life. Acquisition of arcane lore and magical items that aid travel are important goals.