The greatest of them are the Twelve.
Ra-Atum (or Amun-Ra) the Creator, the One Who Stands Behind All Things, Guardian of the Sun, Apophis-Bane.
Usaru the Reborn King, the Green Man, Restorer of the Earth, King of the Dead in the lands of the Duat.
Asarte the Mother, the Protector, possessor of great magic.
Herekh-Montu the Hawk-Warrior, the spirit of the Pharaoh with Ra.
Hathor the Fertile One, consort of Herekh, Merciful, Pleasant-Cow-Eyed.
Ptah-Khnum the Craftsman, the White Bull.
Sekhmet the Wroth, Lion Avenger of Ra.
Sutekh of the Storm, the Usurper, Giver of Rage, Spearman of Sokar-Solar Barge.
Nephthys of the Shadows, the Mysterious One.
Thoth the Wise, Giver of Writing.
Bastet the Beautiful.
Anubis, Opener of the Ways, Finder of the Dead.
Local gods of the nearby temple-precinct or the village must be appeased and their prohibitions respected, or great misfortune can fall upon them, so slaying a crocodile in a town of Sobek will bring his mighty retribution.
No clerics. All can earn the blessings of the god (become priests) they worship of ritually purified and having entered into the mysteries of their God. The supplicant must perform services for the temple, and obey its High Priests (and any dreams or visions), attend festivals. Allows the supplicant to earn a spell or a specific blessing, similar to many cleric spells (DM determined, from the Lamentations rules). Many, perhaps most, high priests are sorcerers, but the majority of priests and are simply functionaries: paid readers of prayers for the dead, scribes, teachers, embalmers, physicians. Sorcerer-priests, generally, are more ethical, including following the Pharaohs laws (he is, after all, the living God intermediary with the other deities), about disrupting the world than a 'free' sorcerer.
All can ask temples for an augury or services, including the learning of spells (Usaru knows necromancy, Ptah and Ra Elementalism). Requires sacrifice and payment, and not be on the temples bad side. Sacrificial bulls or oxen cost roughly 50 sp, while clean sacrificial other animals, like rams, cost 10-15 sp. Auguries cost roughly 50 to 100 sp to perform (the stars must be aligned!). Spell teaching costs roughly 50 sp in sacrifices per day of study, good favor with the temple, and takes 2d6 days. Besides animals, sacrifices to the temples take the form of incense (frankensense and myrrh), linen, good beer, alabaster vessels, and the like.
Visiting temples: only the purified are allowed inside the temple, so the general person must beseech outside. Some temples have guards, but the sorcerer-priests also dissuade many from tempting entry.
The Pharaoh is the greatest priest, son of Ra, the living aspect of the Reborn King, the Warrior Montu-Herekh. His many functionaries may not be priests, but his word is law and he enforces many laws on the use of sorcery, the necropolises, and the temples, in addition to mundane laws.
Demons come from the lands beyond, where the souls of the dead go, they are the guardians of the separation and must be appeased before one can travel to the kingdom of Usaru and the Fields of the Aaru. They also have their own inscrutable purposes and rivalries, and like other entities, can be dominated by knowing their True Names.
The Gods of the North are stern and demanding, aspects of wroth and sacrifice, names like the Horned King, Crom, the Crone, the Raven Queen, the Wanderer. They demand deeds and tests, not mere sacrifices. (That's right, Brom correctly captures their aspects.)
Karolans, followers of Karolus the Conquerer beyond the Mountains of Flame and hills of Koth, worship the One God, died on a tree and reborn in the son;the One God jealous of other gods, though Khemeshi priests explain this is merely the politics of King Karolus who united the barbarians years ago.