Short answers, pulled from the story.
Anubis was the god of funerary rites, protector of graves, and guide to the underworld in ancient Egyptian religion. He was also the patron god of embalmers and presided over the weighing of the heart ceremony that determined a soul's fate after death.
Jackals were associated with cemeteries in Predynastic Egypt because they were scavengers that uncovered shallow graves and fed on bodies. Ancient Egyptians chose a jackal as the protector of the dead on the principle of fighting like with like, turning the animal that threatened graves into the guardian of graves.
Anubis stood at a scale in the Hall of Two Truths and weighed the heart of a deceased person against the feather of Ma'at, the goddess of truth and justice. Souls with hearts heavier than the feather were devoured by the creature Ammit, while souls with hearts lighter than the feather ascended to a heavenly existence.
The parentage of Anubis varied across different eras and sources. Early myths made him the son of Ra; the Coffin Texts named his mother as either Hesat or Bastet. The most widely recognized later tradition identified him as the son of Osiris and either Isis or Nephthys. Plutarch recorded a tradition that he was the illegitimate son of Osiris and Nephthys, then raised by Isis.
Hermanubis was a merged deity created in the Ptolemaic period, roughly 350-30 BC, when the Greek god Hermes and Anubis were combined because both guided souls to the afterlife. The cult was centered in Cynopolis in Upper Egypt, a city whose Greek name means "city of dogs." Worship of Hermanubis continued in Rome through at least the 2nd century AD and the figure appears in alchemical and hermetical literature through the Middle Ages and Renaissance.
Anubis was shown in black for symbolic reasons, not to represent the animal's actual color. Black signified the fertile dark silt of the Nile River, the possibility of rebirth and regeneration, and the darkened appearance of a corpse after embalming with natron and resinous substances.