Each element has a weakness and a strength.
Fire (Element) > Ice (Element) > Wind (Element) > Earth (Element) > Lightning (Element) > Water (Element) > Fire (Element) ... and keeps going.
Additionally Dark (Element) <--> Light (Element) are opposed elements.
Or, if you like lists:
- Fire (Element) melts Ice (Element)
- Ice (Element) compacts Wind (Element)
- Wind (Element) erodes Earth (Element)
- Earth (Element) grounds Lightning (Element)
- Lightning (Element) electrifies Water (Element)
- Water (Element) douses Fire (Element)
- Light (Element) illuminates Dark (Element)
- Dark (Element) eclipses Light (Element)
Certain weapon skills have elemental properties, as well.
Ex: Red Lotus Blade > Fire
See also:
Weather
Ninja: Elemental Wheel