Rot

Rot is the main antagonist of Louse. It is a giant mass of putrid flesh that has always existed. It spread underground for an unknown amount of time before breaking through the surface, in an attempt to turn the surface into its skin. It exists as a pseudo-hivemind, with several connected entities growing out of it. It has an adversarial relationship with the Blot.

History
Rot claims to have always existed. During this time, it spread steadily for years and years, luring pilgrims towards it and taunting the Old Friend while he was on its mountain, before it finally grew enough to break through to the surface. During this time, it also grew multiple parts of itself that controlled various functions of its spread, such as the Brain of Rot and the Heart of Rot. Turmoil was created at some point before it broke through the surface, and was originally rejected by Rot, leaving them to wander the tunnels alone, outside of when pilgrims chose to visit it. Null, the main protagonist of Louse, entered the main mass of Rot soon after it broke through the surface, sliding down inside of it as it began to take the Old Friend's house. Knowing that Null wished to end it, the Face of Rot gave Null a gift, in an attempt to convert them over to its side; however, it failed after an intervention from the Blot.

Repeated attempts were made to stop Null as they traveled through Rot, sending the Love of Rot, the Eye of Rot, and the Sound of Rot to stop them, before they ended up nullifying the Face and eventually the Brain. After the Brain was nullified, Rot no longer had any central intelligence to control its spread, which caused it to begin to spread out of control; in order to combat this, Turmoil stepped into the Brain's old shell, and took control of Rot, so that Null could end the Heart and end Rot as a whole. Before the Brain was fully nullified, however, it said something to Turmoil; the Blot was able to hear that something was said, but was unable to hear what, exactly, was said. Null asked Turmoil what the Brain said, and they said that the Brain confirmed Turmoil's role within Rot as the Seed of Rot; however, they rejected this name, claiming that they are Turmoil, while asking Null to hurry and end the Heart.