Cyberdemon

The Cyberdemon is perhaps the most formidable enemy in classic Doom (although the Spider Mastermind is often a greater threat to the player due to her hitscan weapon). He first appears as a boss at the end of Doom level E2M8, and re-appears in the secret level E3M9, and also on E4M2, E4M6, and E4M7. The Cyberdemon also appears on the retail box cover of Doom II, and is used sparingly throughout that game.

The Doom II manual describes the monster as follows:

''The Cyberdemon: A missile-launching skyscraper with goat legs. 'Nuff said.''

The Cyberdemon is not listed in the PC Doom I manual, presumably to make its climactic appearance in E2M8 a surprise. The SNES manual for Doom I does however mention of the Cyberdemon:

''Cyberdemon: Half unfeeling machine, half raging horned devil. This walking nightmare has a rocket launcher for an arm and will definitely reach out and touch you. Make sure you're loaded for bear before you get to this guy.''

Combat characteristics
It attacks by firing barrages of three rockets. It has 4000 hit points and does not receive splash damage from explosions, making it fairly difficult to kill. It is also the fastest moving monster in the original game, and third fastest in Doom II(after Archvile and Revenant).

Cyberdemon rockets behave exactly as the player's rockets, although they cannot damage other Cyberdemons. Furthermore, the Cyberdemon and the Spider Mastermind take only direct hit damage, and are immune to all blast damage. Therefore, a greater number of rockets is required to kill these bosses than might be expected, and they must be direct hits. The Cyberdemon is given a higher probability of performing his missile attack than other monsters, causing him to launch volleys of rockets at a high frequency. The Cyberdemon does not have a melee attack. In common with other monsters, although the Cyberdemon is shown with his rocket launcher in his left hand, the rockets emerge from his middle.

Tactical analysis
Killing a Cyberdemon is almost impossible without a large amount of ammunition. The BFG is the most effective weapon against a Cyberdemon, although the plasma rifle can work fairly well. Three to four direct hits will kill a cyberdemon. If a BFG 9000 is not available, the rocket launcher is also effective. Around 35 well-placed hits with the rocket launcher will kill a Cyberdemon. Killing a Cyberdemon with other weapons is significantly more difficult: around 400 shots are needed with a chaingun to kill a cyberdemon, for example.

Because a Cyberdemon has a low pain chance, it is difficult to prevent it from attacking. It is also important to be constantly aware of when it fires a rocket, as it will do so relentlessly. Circlestrafing can be used to avoid return fire while attacking. Because one rocket will often be enough to critically injure the player, it is imperative that all rockets are avoided. Because of splash damage, it is also important to stay away from the explosions. For example, it is advisable to avoid standing too close to a wall when fighting a Cyberdemon, as splash damage can be sustained from rockets hitting the wall.

It is advisable to avoid close range fighting if possible, although it is possible to kill a cyberdemon in close range. When attacked at the feet with a chainsaw they have a higher pain chance and cannot aim at a player because of the close range. The Cyberdemon AI is designed to retreat in such cases so this technique can only be attempted in a confined space or to draw hits from imps or revenants to provoke monster infighting. This technique does not work on other Cyberdemons or Arch-viles as Cyberdemons are immune to their own rocket shots and do not take splash. Arch-viles will attack Cyberdemons after being attacked, but the Cyberdemon (as all other monsters) will not fight back.

The Cyberdemon's immense size can sometimes be used as an advantage when attacking it. In some maps, the Cyberdemon(s) are in a large courtyard or structure and the entrance is too small for them to pass through. This can help a novice player to escape if major injuries are sustained.

Appearance statistics
The IWADs contain the following numbers of Cyberdemons:

Doom RPG
In the Doom RPG, the Cyberdemon was created by evil mastermind Kronos, by combining human technology with demon flesh.

Non-Doom games
Cyberdemons are also found in the Roguelike game ZAngband and many derivative games, such as Gumband, Hengband and ToME. There they have similar characteristics to Cyberdemons in the Doom series, although they have been given a tremendously strong close-combat attack (four strokes for 150 damage each) in addition to their traditional rockets. Also, the unique monster Oremorj the Cyberdemon Lord can be found in Zangband and Hengband (Oremorj is Jromero, i.e. John Romero, read backwards).