Revelation (啓示, Keiji?) is a Skill to "hear the voice of heavens" and take optimum action; a Skill equivalent to Instinct, a sixth sense regarding battles. However, "Revelation" accommodates all matters related to the achievement of a goal (for instance, choosing the most suitable path while traveling). Because there is no basis to it (or so thinks Jeanne d'Arc), it cannot be explained to others clearly. It is a Skill held by the soul of the user.[1][2][3]
Solomon received a revelation only once, but based on said revelation, he established a phenomena operation technique - that is, a magecraft that could be performed even by the hands of a common man (up until then, magecraft was the work of only those who stand in row to god).[4][5]
↑Fate/Grand Order Profiles of Mordred, Nikola Tesla, Arturia Pendragon (Alter) (Lancer), Paracelsus, Charles Babbage, Jekyll & Hyde, Frankenstein, Solomon, Arjuna and Karna, translated by Master of Chaos at Beast's Lair.