For other uses, see Bacterian (disambiguation).
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The Bacterian is an evil cosmic force which is composed of most of the enemies the player faces in the Gradius series. Their homeworld is Planet Bacterian, which means that the Bacterian may have come from its original leader Bacterian. Take note, however, that the leader of these evil beings is not always Bacterian, but changes regularly. A brain, a person from the planet Sin, or a giant head have all led the Bacterian Army, although the Brain and Gofer may have been part of the Bacterians themselves. Also, the Bacterian Army possesses the ability to create Organic Fortresses that produce more organic Bacterians so that their Empire can have more territory.


In 6644, the Bacterians invaded Gradius and kidnapped a 3-year old child named James Burton. They conquered five planets and held James as prisoner until 6 months later, a mysterious ship came in, destroyed the Bacterians' fleet, saved James and returned him back to planet Gradius. But the damage had been done; the Bacterians' savage attack on Gradius left amounts of radiation, killing most of the Wreek that lived there.

14 years later, the Bacterians returned to attack Gradius yet again, but unfortunately they got defeated by a 17-year old James and his ship, the Vic Viper, by invading their fortress and taking out the brain controlling it. Not the type of villains to give up, the Bacterians took over a different planet called Nemesis and attacked Gradius again. However, the Bacterians lost control of Nemesis thanks to Vic Viper, but they sent a squadron to attack Vic Viper and a group of Gradian ships. Vic Viper escaped and destroyed the squadron soon afterwords.

In 6660, the Bacterians sent a fleet commanded by Gofer to destroy Gradius but as always, Vic Viper destroyed the fleet by invading their fortress and defeating Gofer. In 6664, the Bacterians took over planet Antichthon, the protectorate of the Gradian Empire, but Vic Viper went in the infected planet and destroyed its mother computer destroying the planet in the process. In 6666, the Bacterians allied with Dr. Venom, who had escaped imprisonment for a coup two years ago. Venom and his Bacterian fleet took over Gradius' seven neo space plants but lost control over them after being defeated by James and his new ship, the Metalion.

In 6709, the Bacterians sent a special force named "Salamander" to invade Latis, instead of Gradius. In response, the Lord British ship of Latis and the Vic Viper ship of Gradius worked together and defeated Salamander by destroying its namesake living base. A reincarnated Venom revived Salamander but was again defeated, this time by the Sabel Tiger and the Thrasher.

One century later, Venom and his Bacterian fleet went back in time to kidnap 3-year old James which ironically led to the war in 6644. In 6840, the Bacterians returned to destroy Gradius. Only this time, the Vic Viper reached the sub-space home planet of the Bacterians and destroyed Bacterian, the central system and creator of the Bacterians.

Years later, a piece of Gofer landed on a planet and transformed it into a fortress. Unfortunately for the regenerated Gofer, he was once again destroyed by Vic Viper. Decades later, a sub-space lifeform named Doom revives Salamander but gets destroyed by Vic Viper and Lord British. In 7240, a piece of Bacterian landed on planet Lamiless and transformed it into a fortress. Vic Viper destroyed the regenerated Bacterian, destroying the planet in the process. In 8010, Venom used Bacterian cells to rebuild his fleet so he can attack Gradius. He got defeated by Vic Viper (and it's future self), returning peace to Gradius. The Bacterians were nowhere to be found at the time of Gradius NEO/Imperial.

Bacterian units

Basic Ships: The Basic Ships are the basic enemies in the Gradius Series. They have cores smaller and weaker than the cores in the Big Core Ships and usually come in waves.

  • Duckers: Small bipedal gun platforms, Duckers are in nearly every stage and possess the ability to run along both floor and ceiling. They are usually rather fast.
  • Hatches: The Hatches generate the Bacterian fighters. Bigger ones are entrances to the Bacterian fortresses.
  • Organic Monsters: The Bacterians can infect any living creature and turn them into corrupted beasts.
  • Big Core Ship: The Big Core Ships are strongest of the Bacterian. Sometimes they're easy to defeat, but sometimes they are difficult to destroy them.
  • Walkers: The Walkers are the last line of defense of the Bacterian. They are often invincible and the player has to go between their legs which is hard.
  • Dark Force: Dark Force is a very powerful mass of energy that destroys anything in its path. Bacterian possesses this power and no one else. Not to be confused with the special Bacterian army also known as Dark Force.
  • Squadrons: The Squadrons are composed of the Big Core Ships, Organic Monsters, and the Basic Ships.
  • Squadron Leader: The Squadron Leaders are the leaders of Bacterian Squads. They follow the orders of the Fleet Commanders.
  • Fleets: The Bacterian Fleets are composed of many Bacterian squadrons.
  • Bacterian Fortress: The Bacterian fortresses are the homes for the hive minds. Sometimes they are thought as organisms due to having the Hive Minds as their brains.
  • Hive Minds: The Hive Minds are the leaders of the Bacterian Fleets. They follow the orders of Bacterian. They are also known as Cyber Brains. Sometimes the Hive Minds are even called Gofers.
  • Zelos Forces: The Zelos Forces are dangerous bionic weapons made to alter the entire planet, resulting in the planet's transformation into a new organic fortress for Bacterian army. Despite being a weapon, it is also a living creature.
  • Bacterian cells: The Bacterian cells are what the Bacterians are made of. These ameboids are parasitic and viral with the ability of controlling matter. They even have the ability to grow into a Hive Mind and command Bacterian Fleets. So every time the Bacterians get defeated, the cells increase in numbers and form new fleets.


These are the tactics of the Bacterians:

  • Bacterian multiplies and forms Bacterian cells.
  • The Bacterian cells multiply to form fleets of mechanical ships and organic creatures. The fleets are headed and controlled by the controllers, or Cyber Brains, who are often located in large Bacterian motherships.
  • After invading and conquering a planet, the Bacterians can transform the planet into any kind of planet. Normally, the Bacterians create a organic planet where they can plan their attacks on other planets. If the controller of the Bacterian-controlled planet is destroyed, the mutated planet will revert back to its previous state.
  • If the Cyber Brain is destroyed, the fleets will break down into Bacterian cells and multiply to recreate their fleet. This regeneration may take centuries, even millennia.

List of Bacterian territory

Here's a list of the known conquered planets and bases of the Bacterian:


Its never been exactly known what the Bacterians' place of origin was; the Salamander OVA stated they were crystal-like lifeforms that spread a fog that transforms planets into Organic Fortresses. On the other hand, Bacterian in Gradius III stated he and the Bacterians were born from the greediness of mankind. If some parts of the Salamander OVAs are canon, this could mean the Bacterians are cells born in crystals from Planet Bacterian. It could be made by humans too by its own greed, evil and lust in order to create a cell of itself in subspace, causing it to infect a whole planetary into a HUGE mechanical fortress.

List of Bacterian leaders


  • The leader is always located at either a fortress or a planet that the leader infects and transforms into a fortress.
  • In each game, all the enemies you fight are controlled by the final boss. So in a sense, you are fighting the final boss this whole time.
  • The Bacterians are known for adapting to several situations, as shown in the Cell levels.
  • The Bacterian possesses the ability to manipulate matter.
  • The energy cores in core warships are control interfaces and also power sources.
  • Whenever a Bacterian lifeform is born, it starts as an organic clump. When its fully grown, it looks completely mechanical.
  • The Bacterian was born in an alternate dimension called Sub-Space. Their fortress, the core of the empire is in Sub-Space itself.

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