Kiba's main character is Zed, a 15-year-old boy who lives in a place called "Calm". He is frustrated by his current situation in life and feels that somewhere out there is a place where he can live more fully. One day, at the invitation of a mysterious wind, Zed dives into a space-time crevasse (portal), seeking the "answer" that might be there. Riding on the wind, he gets transported to a war-torn world where warring magic users called "Shard Casters" fight endlessly with each other, using magical crystals called "Shards". These "Shards" appear to be color coded and assigned an element each: Red is fire, blue is water/ice, yellow is lightning, and orange-brown is earth, purble-black is darkness & green is air. With the power of the Shards, the Shard Casters are able to use magic and control monsters called "Spirits". Fascinated by that power, Zed aims to become a Shard Caster. However, he still doesn't know that residing in his body is "Amil Gaoul", a mighty Spirit with the power to influence the world's future. It also suggests that Amil Gaoul is one of the "Key Spirits" that, when together with the other Key Spirits, can destroy the world. Currently there are four known Key Spirits: Amil Gaoul, Puronimo, Sachira, and Monardi.