Magnum opus is a Latin phrase (used in other ancient languages as well), meaning "the great work". The greatest work of life, that is to achieve immortality. MO = Immortality.
Also note that one does not become all powerful and all knowing when becoming immortal aka. a God, we can say that reaching the MO is just the beginning of the endless journey. For example any of the God we know publicly is incomprehensibly more powerful than anyone who just reached MO.
Also we commonly use Demon to lower immortals and Gods to the most highest immortals but we can say they are all Gods.
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Due to a lot of corruption, destruction of spiritual knowledge by the enemy, and moral/psychological damage that has been deeply embed by the enemy to human beings [let alone psychic attacks to meditating individuals who make it anywhere] a lot of spiritual knowledge, and especially serious...
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