The Trinity Armor is an enemy which can be found exclusively as a boss in the Kingdom Hearts series. 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).
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. 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 Trinity Armor, along with several other Unversed, but soon reabsorbs it.
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 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 these three Unversed combine to form Trinity Armor, they each change shape to facilitate this transformation. 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. In addition, its blue additive splits in half, forming chest decorations. 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 rotate around, and its feet fold inward, becoming heels, with more ornate red feet with black trim being deployed instead. The center leg retracts into itself and flips upside down. The completed Trinity Armor sports three Unversed symbols, one for each of its components.
In Kingdom Hearts Birth by Sleep Final Mix, the Trinity Armor receives a palette swap which gives all three parts a silver body with red highlight throughout it. The U-shaped blade on the α Armor is now gold.
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.