The journey to the West was in truth an expansionist scheme the Buddhist school had spent a thousand years plotting, intended to extend its influence into the Eastern Lands. Tang Sanzang had once been Jin Chanzi, a disciple of the Tathagata. Ten lifetimes of preparation made him a hidden agent of the Buddhist school, and the pilgrimage would allow it to infiltrate the Eastern Lands. Sun Wukong was reduced to the Buddhists' enforcer. With the power of the true scriptures, Buddhism rapidly swept across the Central Plains and Great Tang, replacing Daoism as the dominant faith. Tensions between Buddhism and Daoism escalated, sparking the “Mountain and Sea Calamity,” a great war between the two schools. The Victorious Fighting Buddha, Sun Wukong, was drawn into the conflict by Buddhist rhetoric, and Daoism suffered a crushing defeat due to the imbalance in strength.
Patriarch Bodhi had long foreseen the Buddhist school's ambition to expand and had planted a hidden piece in advance. At its heart was Daoism's supreme treasure, the Sun and Moon Lamp.
