Filtration System

Filtration System is an extremely dark subregion of Subterranean. The maze of pipes and substrates is either pitch black or illuminated by dark red lights, so you can barely see anything besides yourself. Dark conditions combined with the presence black lizards, that hunt by sound and produce little light, make it nearly impossible to survive the region without a light source. Glowstones or the illumination provided from eating a neuron fly are useful in traversing this region. This subregion is connected to Subterranean by four unique tunnels, and serves as the only entrance to the Depths.

Creatures
The following creatures can be found natively in this subregion on all difficulties: The following creatures can be found natively in this subregion on hard difficulty:
 * Batflies
 * Centipedes (infant to overgrown)
 * Scavengers
 * Lizards
 * Black
 * Monster Kelp
 * Big Spiders
 * Spitter Spiders

Food

 * Batflies
 * Blue Fruit
 * Centipedes

Region gates
A karma gate to Drainage System (1 Karma) can be found here.