Seikatsu is a former part of the deity known as One. It is the god of Life. After it's war with Zetzumei which threatened to end existence, Seikatsu was buried deep into the World by the Divine Six.

The Oracle's prophecy states that a Sejurno, a chosen mortal who will be born as Seikatsu, will battle Zetzumei once again and the outcome will ultimately determine the future.