About a week's travel north of RhyDin City lies a mountain range named after its central and tallest peak, Mount Yasuo. Mount Yasuo has long been a place of mystery and intrigue. It is famous for its natural vistas, steep and narrow paths, precipitous crags, high plateaus, and deep valleys. The Yasuo Range is also home to four secluded temples, each located upon one of four mountains surrounding the Mount Yasuo.
The Yasuan way of living is simple. They spend their days striving to perfect their skills of mind, body, and spirit. These are enlightened warriors that have mastered the ways of unarmed and armed combat — and also the mystical chi.
Centuries ago, Anura Khan sought to conquer the known world. Most of the northeastern continent had fallen under his hunger for power. He had a vast army of barbarian warriors, fearsome war engines, and many wizards at his command. On his way to RhyDin City, he chose Mount Yasuo as his next conquest.
A man named Kalfyi San lived on Mount Yasuo, and knew of the threat coming to his city. One of the greatest minds of the time, Kalfyi was a philosopher, sage, poet, inventor, and wizard. He knew that Yasuo's small army was no match for Anura Khan's horde. He gathered eight of the best wizards, and together they built nine towers: one on each of the five peaks and the four plateaus between them. Through these towers, Kalfyi San channeled the power of himself and his brother wizards to create the great Barrier to protect the entire Yasuo Range. Thus the Circle of Nine was born.
Upon reaching the mountains, Anura Khan's army was unable to penetrate the Barrier. The war engines failed to even operate. Angered by this turn of events, he ordered his wizards to destroy the Barrier. During this magical battle, the Nine Wizards made the ultimate sacrifice; they imbued their power directly into the towers to generate a massive wave of mystic power that destroyed Anura Khan, his wizards, and most of the invading army.
Imbued with power, the towers are still maintained and replenished every generation by a new wizard of the Circle — sworn to protect Mount Yasuo and the Yasuan way of life.
In its passive state, the Barrier is merely a ward that prevents other wizards from teleporting directly into the range. The closest a wizard may teleport is a half day's walk away. The energy emanating from the towers also causes machinery and other advanced technology to malfunction in proximity to the Barrier, and to completely stop functioning within it.