Eris

Eris is the goddess of strife.  She is the twin sister of Ares,  she would sometimes accompany him in battles, helping cause qurelles and fights.  Eris would spread roomers about the other gods and she tried to make others jealous of each other.  She helped cause the Trojan war by flinging her "Apple of Discord" into the guests of the wedding of Peleus and Thetis.  This was the plan of Ares and Eris because they were not invited to the wedding.   Three goddesses fought over it.  The goddesses were Aphrodite, Hera and Athena.  Paris was to judge who got the golden apple. Hera offered riches,  Athena offered wisdom and Aphrodite offered to get Helen to marry him.  Paris picked Aphrodite because of her beauty.  When she and Ares were not invited to the wedding of Peirithous and Hippodaneia the twins got all the centaurs so drunk that they started to fight and this lead into another war.