The Way of the Unknowable is an offshoot order of the Way of Shadows, forsaking their dedication to assassination in favor of infiltration. In truth they follow the morality of the Order of the Cobalt Soul, though they shirk the public face they wear. Monks of this order have imbued themselves with the Curse of the Unknowable, forsaking everything they once were to better serve their order.

Curse of the Unknowable

You have been enveloped by the Curse of the Unknowable. This magical aura seeps into every aspect of your being and reshapes how other creatures perceive you. Starting at 3rd level, you gain the following benefits.

• All creatures who knew you before you received the Curse of the Unknowable forget your existence. Their memories are rewritten to either remove you from them or to place another creature in your place, using whichever method will cause as little change in their personality and experiences as possible. Their relationships to other creatures are not affected by this in any significant way (the memories of a friend of yours altered by the Curse of the Unknowable placed upon you will not put a mutual enemy of yours in your place as their friend).
• You gain a new stat called Passive Stealth, which is equal to 8 + Prof. Creatures with a Passive Perception lower than your Passive Stealth will not notice you unless you intentionally alert them to your presence (through actions such as speaking to them or interacting with an object they can see) or they are actively searching for you, in which case their Perception check must exceed half your Passive Stealth in order to detect you (unless you are hiding, in which case they must roll against your stealth check).
• You gain proficiency in deception or expertise if you already have it, as creatures have a hard time recognizing you and your deceptions.

None and All

At 6th level, your unreadability allows you to easily substitute yourself for other creatures in social settings. You have advantage on deception checks made against other creatures to pretend to be another humanoid person, even if you are not disguised. Each time you either provide false information about your identity (such as trying to sew lies or falsify the opinions of your disguise) or fail to know something that the creature you are pretending to be should know, you gain -1 to deception checks made to maintain your false identity until you are discovered or you drop the act (either to reveal yourself or simply leave the area and stop pretending). Once you are discovered or drop the act, you cannot gain the benefits of this feature for 1 day.

Soulless constructs automatically see through this ability.

The Benefit of Doubt

 At 11th level, the Curse of the Unknowable has given you the power to capitalize on other creatures' inability to easily predict your thoughts and actions. You gain the following Ki features.

• Devastating Feint: When you attack a creature with a monk weapon or unarmed strike, you can spend a Ki point to force that creature to make a contested Perception Check against your Deception check. If you fail, your attack misses and you cannot attack again this turn. If you succeed, you gain advantage on any subsequent attacks against that creature this turn.
• Unreadable Presence: When a creature attempts an insight check against you, or when a creature attempts to read your mind, you can spend a Ki point to make a contested Deception check against their Insight. If you fail, the insight check/spell automatically succeeds. If you succeed, you can decide what the creature learns about you or what your current thoughts are to that creature (even if it is untrue).
• Mystifying Escape: You can attempt to weave your curse around the mind of a nearby humanoid, causing them to forget your very existence. As a bonus action, you can force a creature to make a WIS saving throw with a DC equal to your Passive Stealth. If they fail, they forget all actions you made within the last day and you are hidden to them by your Passive Stealth.

False Reality

Upon reaching 17th level, the true nature of your curse is revealed. As a master of it's reality-bending power, you can make the lies you weave into reality. When you hit a creature with an unarmed strike, you can expend 5 Ki Points to attempt to twist their being to your will. The creature must make a WIS saving throw a DC equal to your Passive Stealth. If they succeed, they become immune to this feature for one year. If they fail, you can alter one fact about the creature's cognition such as their alignment, WIS or INT score, their opinion towards another creature, or similar features as determined by the DM.