The Zelos Force are recurring enemies in the Gradius series, first appearing as the final boss of Salamander.
The Zelos are giant creatures created by the Bacterians to serve as planet-modifying systems (implying that they are part mechanical). They take on the shape of a large red eye, though they are able to mutate into other forms and even pilot other Bacterian machinations. Though they were initially defenseless, they later gained the ability to shoot laser beams and homing bolts.
It first appeared controlling the Salamander Planetoid, which led the Salamander forces in their attack against Planet Latis. Upon it's destruction, the planetoid self-destructs. In the MSX version of Salamander, Dr. Venom is reincarnated inside of Zelos, summoning the powerful Metal Slave to fight the heroes. After the ultimate demise of the Bacterion Empire, the Zelos Force becomes free, living in the wild.
Whilst originally appearing as a non-combatant final boss. In a few games, Zelos gained additional attacks:
- Salamander: Zelos' only method of harming the player in this game is to collide with them, as he approaches from behind, it may surprise new players. He will then be held in place by the four stabilizers, these must be destroyed to eliminate Zelos. Upon his defeat, the screen will lurch forward quickly, and the base will attempt to shut the player in - this is very hard to survive.
- PC Engine port of Salamander: In this game, Zelos not only approaches from behind but he also shoots red lightning and his core has to be hit in order for him to be destroyed. Lightning Bolts, however, can remove Options/Multiples when struck.
- Salamander MSX: In this game, Zelos is a free floating entity, and will move around the screen, spawning enemies that will home in onto you. If you can get your option stuck inside Zelos, he will be defeated very quickly. Upon his defeat, Zelos will summon Metal Slave, a very powerful Core Warship.
- Lifeforce NES: Zelos is now protected by a snake creature, which wraps itself round him, firing the occasional fireball. This snake must be defeated before taking on Zelos. It is possible to move around Zelos, but doing this will warp the player back earlier in the game. Upon his defeat, the screen will lurch forward quickly, and the base will attempt to shut the player in - this is very hard to survive.
- Gradius II NES: Appearing in the Boss Rush stage, Zelos will now cause the screen to flash with lightning - this is only for show - his real attack is to create several orbs that will attempt to home into you. These can be destroyed.
- Gradius IV: Upon defeat of Berial, Zelos will appear and grow to massive proportions - he will attempt to destroy the player with a circle volley of lasers. After two volleys, he will automatically self destruct.
- Gradius Gaiden: Zelos will first appear piloting Grave. Later in the game, O.V.U.M. will use Zelos' image as scare tactics.
- He shows up in later games, such as Gradius V as a basic enemy. They can expand their size to massive proportions. And there's a lot of them. And they go "Waaah!" when killed, just like the original.
- In Salmander MSX, Venom is reincarnated inside Zelos and leads the Salamander Attack Force.
- In the PC Engine port of Salamander, Zelos has a covering on his core that opens and closes constantly. This suggests that Zelos is a living mechanical core.
- Zelos Force bears some resemblance to the Kirby character Zero.
- In the Salamander OVA, Zelos Force is seen inside the base of Salamander with a mixing stage of the "Bionic Germ" in both Arcade and the PC Engine, Apparently, he doesn't attack much at all. The Vic Vipers and the Lord British shoot the core of Zelos, which is the only thing that can stop and blow Salamander into pieces (which means in the NES and the PC Engine, you can shoot Zelos' Core)