In a far far away, there is a beautiful land called Claudia, which is blessed by the Ancient Goddess. She is the goddess of life. She created all creatures which inhabit Claudia. After human race creation, the Ancient Goddess slept to recover her magic by human sincerity and love.
However, pure magic which was all over Claudia got unwanted attention. Pure magic is meant to put creatures stay good, but pure magic is not a stable magic. It can be broken by dark magic, which makes creatures vulnerable and cannot control themselves. That is what the God of Chaos is aiming for.
The God of Chaos is the first creature of the Ancient Goddess, or her first mistake. Instead of using pure magic to help guide other creatures to live in peace, he used too much pure magic for his own creations and went out of it. With no more mana to extract from, he decided to withdraw dark magic from the dark dimension. The power was great but dark magic had a great cost: it must consume pure mana from living creations.
The God of Chaos then cursed every creature on sight. Dark mana consumed countless lives in Claudia. With no control over their own bodies, all creatures, including the human race, went on rampage. Wars were everywhere. With a little magic left, the Ancient Goddess sacrificed herself to cure all living creatures and banish the God of Chaos into the dark dimension along with dark magic.
Peace returned to Claudia once again. However, the gate to another dimension remains open in the far west of Claudia. Human race gathered together and formed the Kingdom. They sent their heroes to camp near the dimensional gate to cope with any anomaly. Claudia had 600 years of peace before the first breakout of monsters behind the gate. The world again faced the threat of dark magic, or even worse. The God of Chaos is coming.