Right before the nation of Millena was established, Uniclio Millenas banished a group of humans comprising of several small tribes which opposed strongly the unification plan.
The banished group risked their lives by crossing Lette Plane, a dangerous and undeveloped land inhabited by monsters and unknown creatures, and settled down in the mountainous regions of Southern Crise.
Their settlement was created in a wide valley surrounded by mountains to prevent monsters and any scouts from Millena from discovering their whereabouts.
However, they lacked the resources and manpower needed to create weaponry and equipment to defend themselves. It was during this time that a talented magic researcher among them, Anat Rain,
suggested turning to an ancient sentient race that wielded great power and magical abilities, the Proimas. They began to make contact with Proimas residing in Astral Plane and gained much knowledge about their magic.
The banished people then dedicated themselves to the research of Proima magic. Under the watchful guidance of Anat Rain, who was rumored to have made contact with the ultimate Proima,
the people built themselves a nation they could call their own. They named their nation Rain, after Anat Rain, in recognition of her outstanding contribution to her people.
She also established an academy dedicated to the research of magic for future generations. After her death, the academy produced several other great magic wielders who contributed significantly to the development and prosperity of Rain.