Eris

Eris was the goddess or personified spirit (daemon) of strife, discord, contention and rivalry.

Residence: Erebus
Symbol: Golden apple
Parents: Nyx and Erebus or Zeus and Hera
Siblings: Aeacus, Angelos, Aphrodite, Apollo, Ares, Artemis, Athena, Dionysus, Eileithyia, Enyo, Ersa, Hebe, Helen of Troy, Heracles, Hermes, Minos, Pandia, Persephone, Perseus, Rhadamanthus, the Graces, the Horae, the Litae, the Muses, the Moirai, 
or
Thanatos, Hypnus, the Keres, Hemera, Aether, Moros, Apate, Furies, Oneiroi, Nemesis, Geras, Eleos, Philotes, Oizys and Momus
Children:  Dysnomia, Atë, Lethe, Limos, Algos, Hysminai, Makhai, Phonoi, Androktasiai, Neikea, Pseudea, Logoi, Amphilogiai, Horkos
Roman equivalent: Discordia

Eris Antikensammlung Berlin F1775.jpg
Eris on an Attic plate, c. 575–525 BC.

She was often portrayed, more specifically, as the daemon of the strife of war, haunting the battlefield and delighting in human bloodshed.

Because of Eris’ disagreeable nature she was the only goddess not to be invited to the wedding of Peleus and Thetis. When she turned up anyway and was refused admittance, she raged and threw a golden apple amongst the goddesses. The apple was inscribed “To the fairest.” Three laid claim to it, Hera, Aphrodite and Athena, and in their rivalry they brought about the events leading up to the Trojan War.