The Trinity Armor is an Unversed that is found in Kingdom Hearts Birth by Sleep. It is one of the bosses at Radiant Garden and Mirage Arena. Like the Guard Armor, it is actually composed of three separate Unversed: α Armor (the head and torso), β Armor (the arms), and γ Armor (the legs).
The α Armor contains the Unversed's torso and head. Its head is diamond-shaped and grey with red eyes set in an angry expression. The front of its body is adorned with a large, light blue, U-shaped additive with black edges lined by four shirt spikes. Its "neck" is thin, black, and curls forward. The Unversed symbol is printed on the end of the neck. On either side of the neck, the Unversed has two red "arms" that end in black, triangular blades, each with a yellow stripe on them.
The β Armor takes is cone-shaped and red with black, spiked additives decorating it. The Unversed emblem is on its front. Its base is black with gold lining and four thin, black, propeller-like blades are attached to its top. These blades each have a gold stripe near their tips and the Unversed spins them in a helicopter-esque fashion to move. Its red eyes are on the small spike on its top.
The γ Armor resembles a set of three, segmented, red legs with black and grey joints. The top of the center leg sports two red eyes and acts as the Unversed's "head". The Unversed emblem is small and on the center leg, right below the eyes. Each leg ends in triangular, black feet.
When the Trinity Armor assembles itself, the three individual Unversed each change shape. The α Armor changes very little. Only its head changes, becoming black and sleeker, and it gains a horn on the top of its head. The β Armor compacts and then splits in two, forming the Unversed's arms. The black and gold base becomes the Trinity Armor's armguards and its black and red body becomes two shoulder pauldrons. Thick, light grey arms and black, four-fingered hands reveal themselves from under the β Armor's plating. The γ Armor's side legs remain largely the same as they were before, though the black feet are replaced with more ornate, red and black ones. The center leg retracts into itself and flips upside down. The completed Trinity Armor sports three Unversed symbols, one for each of its components.
The Trinity Armor's name references the fact that it is comprised of three main sections, and the fact that its body resembles armor. α, β, and γ are the lower case forms of the first three letters in the Greek alphabet, and are read as "Alpha", "Beta", and "Gamma", respectively.
In Kingdom Hearts Birth by Sleep Final Mix, the Trinity Armor receives a palette swap, giving most of its armor a bright silver-white color with red highlights. Small sections of its body, like its elbow joints and midsection, become dark blue, and the α Armor's U-shaped collar becomes yellow.
 Kingdom Hearts Birth by Sleep
Terra exits Merlin's house to find the γ Armor fly past him, and he follows it to the Reactor. At the same time, the α Armor appears before Ventus after he is barred from entering Ansem the Wise's castle by Dilan and Aeleus, and the β Armor appears near Aqua after she rescues Kairi from a swarm of lesser Unversed with King Mickey's help. Ventus and Aqua also follow their Unversed to the Reactor, where they run into Terra just as the pieces assemble to form the Trinity Armor. The trio unites to battle it, and are victorious.
Later, at the Keyblade Graveyard, Vanitas explains to a shocked Ventus that the Unversed are his tools. He releases another γ Armor, along with several other Unversed, but soon reabsorbs it.
By now, the player should have a relatively strong sense of Terra, Ventus, or Aqua's strengths and weaknesses, so knowing how and when to use a certain technique should not be an issue. Not only will the player have access to Shotlocks, and Command Styles, but they also will have help from the two other playable characters that were not selected at the beginning of the game, who act as party members. These two other characters have a high power level and do not need to be healed. Should they faint, they will automatically revive themselves with time. As the Trinity Armor is comprised of three separate parts, each will need to be defeated to clear the battle. Thus, having patience is a must. Depending on the playable character you chose, a different strategy will be needed for each. While the battle will be generally the same for all three characters, one must rely heavily on each character's separate strengths and weaknesses to turn the tide of the battle (Terra will excel in strength, Aqua magic, and Ventus speed).
At the start of the battle, immediately Lock-On to one of the limbs. This most likely will be the legs. Begin an immediate offense, but be sure to keep at a constant hit-and-run strategy. A majority of the battle will be spent trying to avoid the Trinity Armor's various long-range laser attacks, so this is important to do. At first, the complete Trinity Armor will attempt to bombard Terra, Ventus, and Aqua with energy balls. Several will spawn, and to top it off, the Trinity Armor will then rush at the player's character. Guard or Reflect (depending on which character chosen) can be used to avoid it. It can also attack by punching. Any counter-type Deck Command can be chained to the player's blocking technique to avoid damage while still harming the boss. Continue an onslaught of attacks and dodge when necessary, and eventually the limbs that the player has Locked-On to will be destroyed, dropping much-needed HP balls as a result.
If only the arms and the torso remain, the two will have a strong chance of double-teaming the trio of Keyblade wielders to shoot a massive laser as they rotate around the battlefield. Continuously Slide, Wheel Roll, or Dodge Roll to avoid the attack, and try to stay near the edge of the battlefield at all times. When the arms are destroyed, the torso will proceed to spin wildly around the area, shooting several lasers in all directions. Again, staying near the edge of the battlefield is recommended for avoiding them as much as possible. Should the torso appear much higher off the ground than usual as it shines with a dark aura, it will proceed to fire a long-ranged laser, spinning in circles as it does so. Bombard the Trinity Armor's torso with aerial combos and magic from behind, and try to stay there until the attack has ended. A Shotlock is also a good way to prevent taking damage from this attack. If the Trinity Armor fires the laser from above, it can be easily dodged with Slide, Dodge Roll, or Wheel Roll. So long as the player remembers their character's strengths and weaknesses, uses all special abilities when possible, heals when necessarily, and most importantly, has patience, the Trinity Armor will eventually fall in defeat.
 Rematches in the Mirage Arena
 Combined Threat
The Trinity Armor returns at the Mirage Arena, fought in the Combined Threat round. Serving as the final boss after five waves of Unversed have been defeated, the Trinity Armor will utilize the same attacks as in its first battle with Terra, Ventus, and Aqua; the same strategies can be utilized to defeat it this time. The only differences in this battle will be the Unversed boss's greatly increased HP amount, the possible presence of any friends if the player selects co-op mode, and the increased power of the player's attacks. Should the player choose to face the Trinity Armor as a different character than the one they originally beat it as in the main storyline, they merely must change strategies to one that suits a particular character's strengths and weaknesses (recall that Terra favors brute strength, Aqua her magic, and Ventus speed). Due to the player's greatly increased power and any help the player may get from friends, the Trinity Armor will be quite easy to defeat, clearing the Combined Threat round once and for all.
The Trinity Armor makes a last stand in the Villians' Vendetta round. The same strategies utilized in past battles can be used to defeat it this time. The player should make sure that their character is at a relatively high level, having his or her most powerful abilities equipped. This will not only ensure that maximum damage is dealt to boss, but also that the player's character takes as little damage as possible. As always, remember Terra, Aqua, and Ventus's different fighting styles, make full use of Command Styles and the like, and be sure to heal if necessary.