From Man to Myth to God: Guan Yu's journey is a fascinating example of historical apotheosis. He began as a real general documented in historical texts. His legend grew immensely through centuries of storytelling, culminating in the 14th-century epic novel Romance of the Three Kingdoms (三国演义, Sānguó Yǎnyì), which fictionalized and glorified his exploits. This portrayal was so powerful that he was eventually deified, becoming a prominent god in Chinese folk religion, Taoism, and even Chinese Buddhism (as a dharma protector).
Embodiment of 义 (yì) - Righteousness & Brotherhood: The concept of 义 (yì) is central to Guan Yu's identity. It's a complex idea of righteousness, honor, and a code of conduct, especially among brothers-in-arms. His oath of brotherhood in the peach garden with Liu Bei and Zhang Fei is the defining story of this virtue. He represents the ideal that loyalty to one's chosen brothers is an unbreakable sacred bond.
Western Comparison: A useful, though imperfect, comparison is King Arthur from British legend. Both are historical figures whose legends have overshadowed their actual lives, and both embody a code of honor (chivalry for Arthur, 义 for Guan Yu). The key difference is the religious aspect. While Arthur is a Christian king, he is not worshipped as a god. Guan Yu is actively worshipped in temples and household shrines, with people praying to him for protection, victory, and even financial success. He is a saint, a hero, and a god rolled into one.