Armored Core Wiki
Prevent Weapon Activation - Nine Ball Unit

Humanoid form

The "Unknown"[1] (labeled "???" in the Japanese version and "Nine-Ball" in the English version) is the final boss of Armored Core: Nexus. The guardian[1] of the Old Weapon Facility under Borbos Mine, it attacks the Kisaragi-hired Raven after they disable the facility's weapon control systems. Its subsequent defeat is followed by the release of countless unmanned suicide weapons that then devastate the surface world.[2]


It appears to have a body similar to the Biped Pulverizer but has the agility of a Hover or Aerial models. It also features a Grenade Launcher on it's back that folds backs to reveal it's head. The unit's arms can fire pulse/plasma cannon rounds in rapid succession and it also possess a vertical missile launcher that can fire up to at least 10 missiles at once.


This machine is fast, agile and deadly and has two forms. The first is it's true "humanoid" form in which it takes right before the battle starts and the other is it's "cannon" form that it is in when it first appears. In its Humanoid form, it is very agile and features a Vertical Missile Launcher that has a large amount of missile launches for its attack, somewhere around 12. It also launchers plasma and pulse rifle shots from its arm. In its "Cannon" form it also adds in a Grenade Launcher.

In its humanoid form, it is very agile and can dodge most attacks while it's Cannon form is stationary. It has full 3D movement capabilities so it's easy to lose track of it.

Fortunately, this unit has quite a low AP value, at the most around 6000 AP, which is only at about 75% of a standard AC's AP value and it does not possess very high defense stats. Therefore majority of weapons in the game will work against it. Rifles, machine guns, sniper rifles and even handguns work well against it. Missiles are a viable tactic but do note that the unit is fairly mobile and is capable of avoiding them, it also seems to possess missile counter of some sort, so the salvoes may not be as effective as they should be. Micro missiles are preferably the best to use against it for this reason.

The unit's main threat lies in its weapon arms, as the pulse/plasma cannon blasts not only have high fire rate, but also packs a deadly amount of thermal stress upon impact, so good energy defense and cooling prowess is vital when fighting it. The vertical missiles salvos also pose a potent threat but it can be averted by anti-missiles or decoys. The unit's grenade launcher is also quite powerful, able to fire up to at least 3 shots in a row, however since the unit has to remain stationary to fire its grenades, it is left vulnerable to your attacks.



  1. 1.0 1.1 Armored Core 10 Works Complete File, page 171
  2. Armored Core: Nexus, Mission: "Prevent Weapon Activation"