There are things that people of this plane aren't meant to see, that their minds cannot comprehend. Sanity is a fragile element of the mind, easily broken by the mere sight of something beyond the reality we see every day. This is where the Xenoseekers thrive.

Walking the tightrope of sanity, and steeped in clandestine operations, these individuals are masters of stealth, subterfuge, and the dark secrets lurking just beyond the veil of reality. Trained to confront horrors that would shatter lesser minds, Xenoseekers blend their roguish talents with esoteric knowledge and covert tactics, becoming the unseen bulwark against the eldritch. 

Cerebral Conditioning

Your training and constant exposure to maddening sights whilst working have jaded you to things that would normally shatter the mind of a person. When you take this subclass at 3rd level, gain resistance to Psychic Damage. Additionally, gain advantage on Intelligence Saving Throws.

Esoteria

Additionally at 3rd level, you gain proficiency in Arcana and Investigation. Also, you can cast Detect Magic a number of times equal to your Intelligence modifier, regaining expended uses after a long rest. You also learn one language of your choice that is typically associated with eldritch beings, such as Deep Speech or Abyssal.

Accurate Acuity

Starting at 9th level, you can choose to use Intelligence or Dexterity for the attack and damage rolls of your weapons. Additionally, your attacks also count as magical for the purpose of overcoming resistances and immunities to non-magical attacks and damage.

If you choose Intelligence, you can add 1d4 Psychic damage to your damage rolls. Increasing to 2d4 at Level 13, and 3d4 at Level 17.

If you choose Dexterity, your sneak attacks or attacks while hidden do not reveal your position. Additionally, you can spend a bonus action to attempt to knock a creature prone. The creature must make a Dexterity Saving Throw. On a failed save, they are knocked prone.

Long Shadow

Starting at 13th Level, you gain the ability to jump between shadows effortlessly. While hidden or standing in dim light or darkness, you can teleport to a location you can see up to 30ft away from you that is also in dim light or darkness. You can cast use this ability an amount of times equal to your proficiency bonus per long rest. Additonally, you can add your Intelligence modifier to Stealth Checks.

Bane of the Eldritch

When you reach 17th level, your expertise at dealing with eldritch beings has conditioned your mind and body even further than before. You gain immunity to being frightened, charmed or petrified. Any Intelligence roll you make that is lower than 12 becomes 12.