Sop

Sop is a being who resides on the island, seen living in both the cave and Sop's House, added in by the Sleep Operation Program.

Story
Sop is first seen in IL06, chasing Georgia as she leaves the cave. Sop is next seen when Eleanor enters the cave in IL07 after Edgar plays the tune seen on the end screen of the game, and we see a close up of Sop after she interacts with it. After they interact, Eleanor is completely removed from the game. Sop's back sprite is also seen on the HUD in IL10, with its resitance show as Braxton, and its weakness shown as Eleanor.

When Edgar plays the tune correctly in ILV13, Georgia exits Tooth Home onto a path leading to Sop's house. Inside, Eleanor can be seen, and Georgia collects her before running back to Tooth Home chased by Sop. However, Georgia is unable to open the cabinet, and is caught by Sop. Eleanor, seeing Georgia's body, is scared, but after seeing the messages of the other island dwellers she opens the cabinet and places a beartrap that catches and maims Sop. Afterwards, Braxton is prompted by Russell to go into the cave, and stomps on the unmoving body of Sop with his salt leg, killing Sop.

After they are forced back onto the island by the storm, the group explore the underground roots, where Sop's House can be seen. Chester enters it against Braxton's will, and sees many Sop beings, causing him to run away. When Eleanor enters the movie theatre a film called Babaptism plays, created by Sop, which shows a baby puppet labelled Edgar being damaged, distressing Edgar. After Eleanor rejoins the group and Georgia's soul hatches, the group form Yotis, and are attacked by the beings seen in Sop's House. This begins a battle, controlled by Edgar, against the final boss.

Sop is seemingly defeated after the battle, however in IL27 it turns out a part of Sop attatched itself to Eleanor when she was taken. Eleanor, under the influence of Sop, kills Chester and Russell - however, with the help of Georgia's soul in the cabinet, Paisley is able to defeat Eleanor, destroying Sop.

Sop isn't seen again until ILV05, where Older Paisley, who has been waiting on the island for three years after the events of IL27, takes Eleanor from the new branch back to the cave to perform a cleansing ritual in order to save their world. Paisley's shield and Eleanor's key are seen to move towards eachother as Paisley chants release, causing a game over that brings Edgar back for a final battle against Sop. After Edgar defeats Sop, they recieve the symbol of truth, and Eleanor wakes up back in the cave alone.

Character
Sop is most commonly seen as an yellow-orange humanoid, with 3 round nostril-like markings and white eyes surrounded by black markings which lead to 3 orange prongs on its head. Its mouth stretches across its face and contains 15 teeth.

Trivia

 * Several parallels can be drawn between the old god mentioned in Russell's story in IL11, and Sop.
 * Gus seems to refer to Sop as old god in IL10
 * The old god was "defeated [...] but not erased", like Sop after the final boss fight.
 * Braxton kills Sop with his salt leg, the old god being killed with a sword of salt.