Armiger

Armiger Arsenal is Noctis's special ability in Final Fantasy XV. After obtaining it, it can be invoked by pressing +  /  +  when Noctis has full MP while in battle. It summons crystal energy in the form of swords to surround Noctis to greatly enhance his battle capabilities, making him faster and stronger and able to continuously use special abilities. The state drains his MP and ends when he runs out. The swords for Armiger Arsenal must be found scattered around the world.

The Armiger system makes Noctis a powerhouse and all of his movements warps, but also makes him able to take on any challenge alone. Because one of the game concepts is cooperation with allies, the Armiger system is intended as a temporary spurt of power for specific situations when the player needs a boost, and is not representative "normal gameplay" that is intended to include co-op moves with the AI allies.

Armiger Arsenal Swords
In Final Fantasy XV Episode Duscae, there are several special weapons that player can find hidden across the massive region.

Aqesiro
Noctis already has the Aqesiro equipped at the beginning of the demo, but the player won't be able to use the special abilities from the sword until after finding the next. The game will then instruct the player how to use Armiger during battle.

The Aqesiro has two abilities, one of which is the Warp Strike that will be performed when player presses and  on the PlayStation 4, or the  and  on the Xbox One at the same time when in Armiger mode. The other ability is the Warp Dodge, which can be done by pressing the and  or  and  simultaneously.

Secace


The easiest heirloom that player has to manually find is located on a cliff northeast of the Digythe Haven camping site.

After acquiring Secace, player will learn how to use Armiger during combat. When player activates it, they will see four phantom swords that will attack nearby enemies.

Galatine


Acquiring the third Armiger Weapon is where things can start to get difficult. The heirloom is located in the Fociaugh Cavern, the southeast area of the map. Before heading there, it is suggested to get acclimated with the battle system, level up a little bit and stock up on a Antidotes and Potions. It is also good to get the second Armiger Weapon to unlock Armiger mode.

With the Galatine in Armiger mode, the player can use the Knightshield by holding on the DualShock 4 or  on the Xbox One Wireless Controller.

Rhongomyniad
The player will automatically get the fourth weapon, Rhongomyniad, by beating Deadeye for the first time. Hunting down the Behemoth is the demo's main quest. After tracking the Behemoth's lair, the player will be forced to enter into a difficult fight.

With Rhongomyniad, the player can use the Knightguard by pressing or  when getting hit, and Noctis will "evade" after the attack and regain the HP that was lost.

Etymology
So far there are many references to King Arthur and his knights. With the tagline for the current trailer being "reclaim your throne" and the central theme of brotherhood it can be suggested that the main story will mirror Arthurian legend.

Secace is the name of one of Sir Lancelot's swords.

Galatine is another name for Galatyn.