Eris

Both of my mythology books say that Eris was the daughter of Nyx, the personification of night. Although I think her parentage is diffrerent in some myths, kind of like Aphrodite's parentage.

Eris began the Trojan War by presenting Zeus with the golden Apple of Discord. Three Goddesses (Aphrodite, Hera and Athena) wanted the token and Zeus, not wanting to choose between them, gave the Apple to Paris of Troy. Each goddess promised him something different but he eventually chose Aphrodite as she promised him a woman as beautiful as herself, Helen of Troy. Helen then fell in love with Paris and sailed away with him to Troy, beginning the war.

Zeus did NOT get to choose between the goddesses, as it was claimed in the comment above, but the prince of Troy - Paris. Eris, angry for not being invited to the wedding, threw a golden apple with the carving "To the most beautiful one" in the room the wedding guests were celebrating in, and all Hera, Athene, and Aphrodite claimed it as their own. Paris was chosen to resolve their dispute. All three goddesses tried to plese him promising him all sorts of glorious things they had control over. He ended up choosing Aphrodite because she promised him the most beautiful woman in the world, Helen of Troy.

Eris was the goddess of discord and chaos. She took pleasure in seeing confusion and anarchy.