Over the years, humanity spread its fingers over the surface of Earth. They left nothing untouched. Now, they can only build upward, leaving behind the poor and unfortunate to struggle on the forgotten ground below.

Once a person from those upper areas who lived in bliss during his youth, Sigmarus Grayson gradually lost everything and was banished to the streets below. Eight years into his suffering, he discovers a briefcase holding the item that will change his life forever.

Thus begins the journey of the RPG Immortal.