For example, there was a skill called Delusional Poison Body: Zabaniya, which had once been wielded by an Old Man of the Mountain known as “The Tranquil.” The power that “The Tranquil” herself had acquired had been truly fearsome. It had turned every part of her, including all her bodily fluids, her nails and skin, and even her breath, into deadly poison. A dreadful legend told how she had slaughtered an entire army by spreading her poison in the wind. Assassin, however, merely mimicked that power temporarily by concentrated poison in her own blood. It was said that this was because she imagined a scenario in which indiscriminately scattering death on her surroundings might result in the deaths of comrades or innocents, and the concentration of the poison was consequently reduced.

Fate/Strange Fake: Volume 2, Chapter 5 ("Day 1, Dawn")