Armored Core Wiki
General information
Classification Battleship
Appearances Armored Core V

The St. Elmo is a boss encountered in the multiplayer of Armored Core V. It is a heavily armed literal battleship.


St. Elmo is a massive trimaran-hulled battlecruiser bristling with a variety of weapons. A perfect littoral combat ship, it is able to project its massive firepower at all ranges and nearly all directions, making it very difficult to destroy. Furthermore, the player faces not one, but two St. Elmo units. This is reflected by the unit deployment position that is divided into two attack formations.


  • 7x Twin-barreled Sniper Cannon. Three at forward side, two on each port and starboard side. Attack power rated at approx. 3000+ KE.
  • 6x CIWS. Specializes in shooting both missiles and AC. One front, one rear, two on each port and starboard side. Attack rated at 300 KE.
  • 3x Vertical-launch missile tubes. One front, and one on each port and starboard side. Each tube launches approximately 8-10 missiles. Attack power rated at around 800 CE per missile.
  • 1x Giga Missile Launcher Platform. Capable of firing one Giga Missile every 2 minutes, with launch time 10 seconds after launch hatch opens and launcher moves into firing position.

Combat Characteristics[]

St. Elmo is well defended in all aspects. At extreme ranges, the sniper cannon allows it to deal massive damage to slower moving targets. The missiles, while not usually lethal on their own, are used mainly as a harassing weapon, capable of damaging maneuverable units. Its CIWS are not strictly a defensive weapon, as it is capable of stunlocking an AC straying into its firing range, thereby opening it up for attack with other weapons. Finally, not only the Giga Missile is capable of one-hit killing any AC it impacts, it is also used for flushing out ACs in hiding so that other weapons can get a shot. In short, St. Elmo is, for all intents and purposes, a floating fortress.


To defeat St. Elmo, its weakness, the Giga Missile Launcher, must be destroyed. If it is destroyed, the entire ship sinks. It is possible to bypass all conventional warfare methods and employ an Overed Weapon to destroy St. Elmo. Conventional weapons can and will destroy the Giga Missile launcher, with slight difficulties.

However, in order to obtain S Rank, all turrets on-board St. Elmo must be destroyed manually. To do this, an AC can approach St. Elmo from behind, where it is guarded only by a CIWS turret. Once the CIWS turret has been eliminated from behind (mounting your own CIWS shoulder unit to prevent missile attacks is a good choice) using a longer-ranged weapon, an AC may board the ship and start to destroy the turrets at leisure. Be warned however that the Giga Missile launched will hit an AC even if it is standing on top of a St. Elmo, while St. Elmo itself will not take damage from the Giga Missile explosion. Since the two St. Elmo's rarely (if ever) intersect firing distances, it is rare that you will be under attack from the other unit.

KE and CE defenses are prioritized, as St. Elmo carries only conventional weapons on-board. Despite so, its sniper cannon is absolutely devastating, and the CIWS' stunlock capability is nothing to scoff at. St. Elmo is by no means an easy opponent, but those that are patient can defeat this behemoth twin.


  • St. Elmo, or St. Erasmus of Formiae, is the patron saint of sailors.
  • St. Elmo's design slightly resembles the BFF Battleship from Armored Core 4 and Armored Core: For Answer
  • Unarmed St. Elmos may be purchased as part of the "Naval Fleet"-themed Garage decorations, much like helicopters, barrels, trucks, and others from other themes. They do not have any in-game benefits however.