Attire

Attire is an option under Gear in Final Fantasy XV. The attires worn by characters change how they visually appear in the field, but they also add additional effects to the wearers. These effects apply after all other effects, so if other gear increases the user's max HP to a new value, then attires that increase the max HP will increase by a percentage based on that new value.

Terra Battle
Noctis appears as an obtainable character during the Final Fantasy XV collaboration event. He has three costumes based on his attires from Final Fantasy XV.

Trivia

 * Square Enix announced a DLC outfit Magitek Exosuit for season pass holders, but it was never released because the publisher of Power Rangers thought the design was too close to their intellectual property. The costume will be released "at a later date."
 * A model of Noctis with his original attire used for the Final Fantasy Versus XIII reveal trailers is found dummied on the game disc, but is not an equippable attire.
 * Gladiolus's Rugged Attire doesn't have the scar across his chest in Chapter 14 his Crownsguard Fatigues show.
 * The Kingly Raiment has a version without the cape, as the penultimate boss destroys the cape and Noctis goes the rest of the game wearing the suit that was under it. This suit was actually made for Final Fantasy Versus XIII and for the opening.
 * If the player equips the Kingly Raiment without the jacket for the final boss battles, after the cape is lost Noctis will be battling without his suit and using just the dress shirt.
 * After completing Episode Prompto, the player unlocks his Tundra Attire. The notification for this says "Change into your new outfit and let the cold know it never bothered you anyway!", a reference to the song "Let It Go" from the movie Frozen.