The Egyptian goddess Isis was and continues to be an extremely popular and well-known figure. She was a mother goddess as well as a goddess of nature, fertility, children, magic, and love. Isis was also linked to death as a protector of the dead (as explained in the myth of Osiris).
The goddess is normally shown as a tall woman wearing a plain sheath dress to her ankles and crowned with the hieroglyphic sign for “throne”. A common depiction was also of Isis holding or nursing her son Horus. In other images (the most common ones), Isis holds the ankh in one hand and a plain staff in the other. On funerary coffins and inscriptions, Isis and her sister Nephthys are shown with outspread wings, to show their status as protectors.
Isis was the daughter of Geb, god of the Earth, and Nut, goddess of the sky. Her brother (as well as husband) was Osiris. Her two other siblings were Set (god of storms and chaos) and Nephthys (goddess of lamentation and the night). Isis was the mother of Horus, hawk-headed god of the sky, war, and vengeance.
The main myth of Isis involves both Set and Osiris. Set created a beautiful box and said that whoever could fit inside it perfectly could keep it. What the gods didn’t know was that Set had secretly measured Osiris while he slept, so he would be sure to have the exact fit for Osiris. The gods took turns, and then Osiris stepped inside to see if he would fit. When all of Osiris was inside, Set slammed shut the lid and it became a coffin. Set took the coffin and threw it into the Nile where it drifted away. Isis went looking for the coffin to give Osiris a proper burial and found it in a tree in Phoenicia. She brought it back to Egypt and hid the coffin in a swamp.
But Set went hunting that night for the coffin and when he found it he was enraged. He chopped Osiris’ body into fourteen pieces and scattered them over Egypt. Isis and Nephthys went searching for the pieces in order to properly bury Osiris but could only find thirteen of the fourteen. The last piece, Osiris’ phallus, had been swallowed by a fish. So Isis fashioned a new one with her magic (some myths say she first made a phallus of wood and used her magic to attach the replacement, but usually it’s just mentioned that she corrected the problem of the fourteenth piece with magic). With all the pieces assembled, Isis was able to resurrect Osiris with her magic, after which they conceived Horus.
Sometimes it is said that the Nile floods each year because of Isis’ tears when she searches for Osiris’s parts.
Later on Isis merged with Hathor, the goddess of love and original mother of Horus (who originally was Isis’s husband rather than Osiris). Because of the merging of the two beliefs and the institution of Osiris as Horus’ father, Horus was then brought into the struggle with Set, who wanted to kill Horus as well. Isis fled with Horus and protected him until he was old enough to fight Set and become Pharaoh of Egypt.
In addition to assimilating Hathor, Isis also merged with Mut in popular belief. Mut was a primordial deity from before the creation of the gods. She is said to be the original mother from which the cosmos sprang. Her properties by themselves coincided well with Isis, but Mut was the consort of Amun, which created problems in the stories later on when things did not match up well.
On her Light side, Isis was a life-giver and life-restorer, in that she was a fertility goddess and protector of the dead. By bringing Osiris back to life with her magical powers, she is then linked with resurrection, rebirth, and reincarnation (to a certain extent). Although not strictly a goddess of the dead, she does seem to have some influence in that realm in that she protects burial rites, the dead, and those who would enter the afterlife. Primarily Isis is a goddess of life, nature, fertility, and magic.
Isis, from the mythology alone, does not appear to have much of a dark side. She seems to be wholly good, as a mother, magician, and protector. She does not seem vindictive or hateful, or overbearing. Therefore it is harder to find a Dark spot in her. It could be argued, I suppose, that her Darker side is shown when she protects Horus so he can kill her brother later in vengeance–but that episode could also be seen merely as a mother protecting her son from his mad uncle.