Pearl of Wisdom

The Pearl of Wisdom (聡明の玉, Sōmei no Tama) is one of the most powerful and dangerous Secret Treasure that currently exists. Not much is known of its history, however Iscariot has deemed its power to be capable of plunging the world into chaos if mishandled. It currently resides within their Dark Vault.

Description
This dangerous item, like many others that are classified as a Secret Treasure, possess a seemingly unassuming appearance. It is small and round in shape, easily fitting within the palm of one's hand. It's magic output is among the lowest, so considerable talent or concentration is required in order to sense its presence. Even more so, when it is attached to its victim, as their own magical power can conceal it.

When not in use, it takes the shape of a simple pearl of perceived low quality. Its color is white, dull of depth and appearing rather dirty and worn out. Many simple folk would be fooled into believing it has no value, which is why it is considered so dangerous, as almost no one would suspect it as an object of great power.

Usage
The pearl has several uses, which revolve around telepathy, memories and the mind in general. The less dangerous one is when its user employs it on someone else. To do so, they place it in the ear of an intended victim where it attaches itself to the inner ear. The process is slow, but its effect is steady, gradually granting the user control over the thoughts and actions of their target.
 * Subliminal Telepathy: The most basic method of gaining control over someone's mind. It is fundamentally similar to hypnosis, however its power is most potent when the target is asleep. As a whole, it is very difficult to control people's perception if their subconscious does not agree. Their conscious mind uses logic and reason as a form of mental shield to deter them from perceived unfavorable thoughts and actions. So the pearl does not force one to do or think anything, rather guides them through subliminal stimuli during deep sleep.

The process induces controlled, dream-like illusory scenarios, in which the responses of the target shape the environment and their experiences to suit the user's intentions. Experienced users usually mask their intentions by recreating memories of the victim's past. For example, it could be a memory from their childhood, in which the victim did as they were told by their parents. Eventually, the user will make small changes to that scene, such as the environment, action that was performed and even their thoughts on it. When they attempt to resist or outward deny any suggestions implanted into them, the pearl will reshape the dream world using specific scenes that aim to elicit a negative emotional response, like fear or revulsion. At the same time, actions or thoughts considered favorable to the user aim to reward the victim with scenes that will elicit positive emotional responses, like happiness, satisfaction or even pleasure.

These dreams will be immediately forgotten upon waking up, however the feelings associated with their responses within the dreams will remain. When faced with similar situations, they will inexplicably feel the intended emotions. Slowly, but surely, the user will manipulate their victim by giving them false experiences, making it seem as if they were doing things of their own free will. As a testament to its power, it transformed an honorable, honest and altruistic monarch who loved his kingdom and aimed at its prosperity into a mentally unstable despot, paranoid and delusional of everyone around him that terrorized his subjects and started wars. That same king caused the destruction of his own kingdom and neighboring territories, where an innumerable lives were lost.