Apis was an Egyptian bull-deity worshiped in the Memphis region of Egypt. According to Manetho, his worship was instituted by Kaiechos of the Second Dynasty. Apis is named on very early monuments, but little is known of the divine animal before the New Kingdom.
Ceremonial burials of bulls indicate that ritual sacrifice was part of the worship of the early cow deities and a bull might represent a king who became a deity after death. He was entitled "the renewal of the life" of the Memphite god Ptah: but after death he became Osorapis, i.e. the Osiris Apis, just as dead humans were assimilated to Osiris, the king of the underworld. This Osorapis was identified with the Hellenistic Serapis, and may well be identical with him.
Greek writers make the Apis an incarnation of Osiris, ignoring the connection with Ptah.
"The holy beast of Ptah, the creator god of Egyptian mythology, seen as an incarnation or agent of Ptah. Apis takes the form of a cow with 29 distinct features on its body. It is said that there can only be one Apis in the world at any given time. When a new Apis is found, the previous Apis is drowned in the Nile. When the Apis reaches its natural lifespan and dies, it is mummified and given a solemn burial. After Death, the Apis is said to be reincarnated as Osiris."
—Shin Megami Tensei IMAGINE compendium
Apis can be contracted in the bronze level instance of Shibuya's Celu Tower, while more powerful versions can be encountered in the other versions of the instance.
Shin Megami Tensei: Strange Journey
"The bull-god of Ptah, the god of creation in Egyptian lore worshipped in the Memphis region. Apis was conceived by the union of a cow and a ray of light from the heavens. It is said to have 29 distinct identifying attributes, such as a diamond on its forehead and an eagle mark on its back."
—Shin Megami Tensei: Strange Journey compendium
Apis appears as a summonable demon. As a member of the Holy Race, though, he will not appear as a recruitable demon in the field.
Shin Megami Tensei IV Apocalypse
Apis can be found within the Toyosu Shelter and the Konganji Passage in Ginza. It can teach the Hama, Critical Wave, Tetraja and Media skills through its Demon Whisper. Apis benefits from learning Light and healing skills.
Devil Survivor 2
"A bull god and herald of Ptah in Egyptian lore. He was worshipped in the Mephis region. Apis was conceived by a ray from the heavens. He is said to have 29 distinct features, such as a white triangle on his forehead, a pattern that resembles a vulture, and so forth."
—Devil Survivor 2 compendium
Shin Megami Tensei: Liberation Dx2
"The bull-god of Ptah, the god of creation in Egyptian lore, deeply worshiped in the Memephis region. Apis was conceived by the union of a cow and a ray of light from the heavens. It is said to have 29 distinct identifying marks, such as a diamond on its forehead and an eagle mark on its back."