Styx: Hate Goddess as a Source of Strength?

This week we look at the daimonic goddess Styx, who is a personification of the river in Hades, but is also associated with Hatred. Her children are Victory, Force, and Rivalry, and Zeus rewarded her help in the Titanomachy by making the gods swear oaths upon her waters. Why do the qualities of a valiant warrior have their origin in a god of hatred? Is it a statement about war, or something else? The psychological possibilities may surprise you.