Gods are a race of immortal higher beings who control the forces of nature and human endeavors. They are the descendants of the older Titans, their ancestors and chief enemies. There are currently twelve major gods, the Olympians, who rule over the universe, all of whom are under the rule of Zeus, god of the sky. There are many other minor gods who serve smaller but necessary purposes in the world. Despite their immense power, they are subject to divine laws, and, in theory, cannot break oaths sworn upon the River Styx. However, due to their immortal nature, breaking such oaths does not have severe consequences to them. Although the word "god" can be gender-neutral and applied to either female or male, the gender adapted terms for a male would be known as "god", whereas a female would be called a "goddess".