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The subject of this article appears in the Metro 2033 novel. The subject of this article appears in the Metro 2033 video game.

 Biomass has other uses. Please see Biomass (Disambiguation) for other meanings. 

The Biomass is the term given to the amorphous creature of the Kremlin in the original novel, and the boss-like creature Artyom and Miller face in the D6 Reactor of the Metro 2033 video game.

Game Overview[]

If hell exists, I think we've found it. And maybe Satan himself is waiting for us up there.

— Miller

In the video game, the biomass is a giant biological mass on top of the reactor in D6, found in the Biomass level. It has an amoeba pore and several giant tentacles used in killing anyone trying to separate it from the reactor. It draws power from the reactor, which is why it attempts to stop Artyom from activating it. Artyom must run past the creature to the crane and manually lift each cell up to activate the reactor, before the biomass destroys the crane.

After the reactor is activated, and the Biomass quelled, Miller mentions that they should return to "finish what [they've] started, but after [they've] dealt with [the] dark ones". Artyom and Miller then leave the injured biomass to head to the tower on the surface.

In Metro: Last Light, two notes found in Red Square describe a creature living the Kremlin that lured creatures to it - which is very much like the Biomass in the novel as described below.

Note 1[]

"What is it like, the Red Square? I can't wait to see it. People before used to say it was the heart of our motherland. I'd never been to this place, and saw it only on the old postcards. This must be the most popular postcard sight of Moscow. - the Saint Basil's Cathedral, the Kremlin... All the foreign tourists used to be brought here first and foremost... They didn't nuke the Kremlin in the War. Instead they hit it with something... Something that spared all the buildings but ate everything organic within the radius of a few miles. Something... experimental."

Note 2[]

"For years nobody dared approach the Red Square. They said that something remained in the basement of the Kremlin, luring anything alive in and consuming it. Then the Order purged the Kremlin with fire... it's empty and all black with silt inside now. Just like the rest of the city. The Red Square. The stopped heart of a country long gone."

The Kremlin and its attracting powers appear in the 2033 novel, while in the Last Light game, Artyom is able to traverse the Red Square just fine, showing that the purging of the Kremlin happened somewhere between the events of 2033 (both novel and game) and Last Light.

This suggests that the Biomass is the product of some chemical or biological weapon. This rumor can also be heard by eavesdropping at the Market in 2033.

In the Novel[]

In the novel Metro 2033, the biological mass is hidden in the station under the Kremlin and has the power to attract its victims by, presumed, psychic powers, similar to that of a carnivorous plant's odor to insects. People thus affected feel the urge to walk towards the biomass and submerge themselves in it, where it slowly consumes the body of the victim. It is suggested to be the entity that causes stalkers who look at the star of the Kremlin to travel there as to feed themselves to it. In the novel, Artyom and the group of stalkers that encounter the creature when they arrive at the station underneath the Kremlin. At first, the station seems pleasant and in pristine condition. When they step on an escalator, and it starts descending , they realize that their state of mind is being manipulated by the biomass, who is at the bottom of the escalator waiting to absorb them. They take refuge on a train car, only for the biomass to surround them and start psychically attacking them once more. They manage to escape the biomass by throwing a flamethrower gas canister towards it and shooting the canister to explode it, making it retreat and giving the team enough time to escape. In the novel, it's estimated that at least three people are killed and, presumably, consumed by the biomass, an unnamed stalker, a stalker called Oganesian, and Oleg.


  • Near the ladder Artyom must use to reach the crane in the reactor chamber, a long, tube-like tentacle clings to the wall. An opening in the end of the tentacle vents large quantities of shimmering hot air, possibly as exhaust. This might be part of how the biomass lives on the energy of the reactor, or might simply be a means of ridding itself of excess heat.
  • Judging by its attempts to defend itself, the biomass seems to be unusually intelligent. To keep Artyom and Miller from re-activating the reactor cells, it first attacks and damages the control room, then attempts to destroy the crane cabin. This suggests that it is somehow aware that these mechanisms will affect its ability to live off the reactor.
  • The Biomass remains radioactive even after the reactor is reactivated.
  • The origins and general appearance of this Biomass are very similar to the Master from the video game Fallout: A Post Nuclear Role Playing Game. This excerpt is particularly similar:

Grey was plunged into a vat of F.E.V. by a robotic arm. Floating in the vats for almost a month, the F.E.V. transformed Grey into the amorphous, blob-like being that would eventually become known as the Master. This entity expanded its biological mass by absorbing other creatures and people that came near the base, and bionically merging itself with computer equipment from the base. The ones he consumed also became part of his multiple personalities. It also began capturing humans that stumbled upon its lair, and intentionally exposing them to the F.E.V. These initial mutated humans were incredibly flawed, and the newly named Master consumed them rather than letting them live. (...) The Master has extremely powerful psionic abilities, able to project extremely vivid hallucinations that easily break the mind of any enemy without some form of mental protection. Besides his psionic abilities, the Master also has a genius-level intellect and incredible natural charisma, having rallied an army of sycophantically devoted human and super-mutant followers around him.

This might be due to the fact that the original Metro 2033 novel was roughly inspired by the Fallout universe, as Dmitry Glukhovsky has admitted.

  • The Biomass in Metro 2033 doesn't seem to consume humans as the novel describes, but is still extremely aggressive to the presence of humans.
  • In the Market, it can be heard that the Kremlin was hit by a secret biological weapon, which explains the origin of the Kremlin creature and why most of the Kremlin wasn't destroyed.



The Biomass Creature in Metro 2033 Redux Crane, Proposed Infection, Lore, and Morphology

The Biomass explained