A Yi is someone who assists another.
Thousands of years ago, the central pillar of the great formation that protected the civilization of the Greater World was lost in an accident!
To fend off invasions from other civilizations, the guardians of the formation's central pillar must search throughout the Greater World for suitable Yis. They will become pillars themselves and join together to protect their civilization.
For reasons unknown, this mission fell to a mysterious organization, which set out on the search for Yis itself.
They discovered that the first stop was a mundane world that had developed modern technology!
Yet it is here that the Yis will embark on legendary journeys across the world, making a name for themselves and proving their extraordinary worth! Like sparks in a modern city, they will become a prairie fire and shake the immortals in the heavens!