Saints possess an innate bodily characteristic, allowing them to assume a portion of the Son of God's attributes, blessing them with superhuman strength, speed, sense, healing and the capacity to channel larger amounts of mana compared to normal magicians. The structure behind Sainthood is based in Idol Theory, where an imitation of a more powerful being or item can retain a small portion of the original's strength. Humans are said to be made in the image of God and a Saint is said to be a higher replica that can draw out more power.

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All of them were a great force that represented Britain and they were all either a Saint or the possessor of an equivalent level of power. They would occasionally move at greater than the speed of sound, they would occasionally singlehandedly wipe out an army, and their power was said to be proportional to a nuclear weapon.

Toaru Majutsu no Index vol.4, Toaru Majutsu no Index New Testament vol.10