Kairu is a primordial energy source that is used by warriors in order to transform into Redakai. Warriors using Kairu can gain incredible strength, lightning-fast speed, and superhuman mental powers. The most powerful Kairu warriors join the ranks of the Redakai, a force dedicated to protecting the galaxy from those who would abuse the power of Kairu. It is also used in the TCG in which it is used to activate abilities among other things.
- Kairu is similar to Mana from the TCG, Magic: The Gathering in how they are used and they gain one each turn.