Sotiris is a mysterious entity created by Dr. Piccinini with the purpose of being his savior. The creature was given life and nourished by him in the Neizumi Testing laboratories, and it is presumably the reason why the laboratories have been abandoned. It's unknown how Sotiris was created, but it's suggested it was a combination of scientific testing and supernatural means. Sotiris can teleport, can kill the player by simply touching them, and also can break the game, by messing with it's code (notably the fake credits roll, and turning Dr. Piccinini into an item)
It's suggested that the idea to create Sotiris was given to Dr. Piccinini after he listened to Tape #3. (likely influenced by bayagototh considering the lab's notes about the Tape)
Sotiris can be first seen after opening a door that leads to the area he resides in. if the player attempts to attack him, he will kill the player, letting rats get nearby and eat the player's body, eventually ripping out their eyes. The player needs to collect an eye from one of the piles of flesh in the area, and a while after finding one sotiris will be seen inserting the eye into their "eye-holes" then, sotiris will always have the eye looking at the player, however still not being able to move. Then, the player needs to get to a door locked by an IRIS scanner to then, get to an elevator. This is the last area where Sotiris is encountered, launching a fake credits roll and likely dying in the fall of the elevator.
Sotiris can't be killed, but it can't move while in the line of sight of the player. It can, however, chase the player around by teleporting to a radius around the player. He teleports when the player looks away for at least one second, and the radius shrinks as you stay in the area for too long. It also shrinks faster if the player is not looking. As long as the player looks towards its general direction, regardless if there are any boxes blocking their path, Sotiris can't move. The only way to escape is by collecting the eye of Dr. Piccinini in a random place in the area, and using the eye to open the door.
In the Elevator
While riding the elevator after escaping Sotiris, the entity begins to break the game by making a fake credits roll. It will then appear hanging in the elevator, then shortly breaking it to make it go towards the game's last area.
"The need for eyes, is an unquenchable THIRST"
-fake credits roll