Who Prajapati is
Prajapati is the father of the Vedic world. His name means lord of creatures, and by the end of the Vedic age the priests held that the gods, the Asuras, people and animals had all come out of him.
In the Rigveda he arrives late. The word appears a few times as a title of other gods, and four times in the tenth and last book as a god in his own right, asked for children and for fertile cows. One hymn is his own. Rigveda 10.121 praises a god who arose in the beginning as a golden embryo, propped up the sky, owns the snowy mountains and the sea, and gives breath to everything. Nine verses end with the same question, which god shall we honour with our offering. The tenth answers with his name.
Prajapati, you alone hold all these born things in your arms, and no one else does.
Two other hymns of that last book ask how the world began without naming him. One tells of the cosmic Person, Purusha, whom the gods offered up, so that the sun came from his eye and the moon from his mind. The other, the hymn of creation, begins before there was either being or not being, and ends by wondering whether even the one who watches from the highest heaven knows how it happened. Later teachers read Prajapati into both.
In the Brahmanas, the prose books of the priests, he is everywhere. Story after story opens with the same words: in the beginning Prajapati was alone here, and he wished to be many. He does not create by command. He toils and heats himself with effort, and the worlds come out of him. The work costs him. He is emptied by it and falls apart, and the gods have to put him together again with fire. The priests said the great brick fire altar was his body, rebuilt each time it is built.
He is also the year, because the year wears everything away and brings everything back. He is the sacrifice, which he made as a likeness of himself. And he is a teacher. In the Upanishads the gods and the Asuras both sit at his feet as pupils, and he gives the same lesson to each and watches to see who understands.
He has no weapon and fights no battle. What the texts give him is work, weariness and patience.