The necessary context you're missing to understand Asura's Wrath is Buddhism. The whole game is a pastiche of the first "arc" of Journey to the West, as Sun Wukong rebels against Heaven and is punished for it by the Buddha and his giant finger. In that story, Sun Wukong is in the wrong and acts out of wounded pride, but Heaven is just as spiteful and prideful. Anyway, there are also elements specific to Japanese Buddhism, like the Eight Legions and the Daibutsu. Hope that helps.
Come to think of it, this isn’t the first time I’ve heard about Journey to the West, but I haven’t read it myself, and unfortunately my knowledge of Buddhism is both limited and diluted by the Western filter of what it thinks Buddhism is. /o\