- PDA contact biography
- A mysterious Sin character that follows the player throughout the course of the game.
- Also (and only) known as ". . ." if the player manages to place a rangefinder on him.
- The player is not privy to his motivating raison d'être during the game other than an assumed servility towards his "overlords" during the Swamps Oso cutscene.
- Causes a major dispute between Duty and Sin during the course of the game, which can lead to the complete destruction of the latter (only if the player previously joined Duty)
- Appears to the player in numerous cut-scenes throughout the game:
- The player has no effective contact with this character other than occasional cutscene glimpses.
- The Sin Spy takes up a recon position atop the Radar Station in Yantar after the Swamps cutscene.
- Close approach will cause him to teleport away from the area as will any attack attempt from range.
- Very early game releases (v 1.30013) could spawn a Blowout that killed him at this location enabling him to be looted for a Strange psi-helmet, but this content was subsequently cut from the game.
- Traveling through the Yantar underground underneath the Radar Station will not cause him to teleport away, although visible on the mini-map as a yellow beacon, his PDA remains partially cloaked (no bio information)