Testament

The Testaments are a group of cloaked men in the Xenosaga trilogy. They are associated with Wilhelm.

Episode I
The Red Testament is first seen with Wilhelm discussing about the information they have been reported on by KOS-MOS. The Blue Testament later attacks the party in the Song of Nephilim, allowing Albedo to escape. The Blue Testament later reveals himself to be Luis Virgil on top of his E.S., Naphtali while observing Proto Merkabah while complaining to the Red Testament to not to talk to him telepathically. In the ending, the Red Testament is talking to Wilhelm, saying Albedo is the only one who can open the gate to Abel's Ark.

Episode II
The Red Testament is seen speaking with Wilhelm, telling him that they've detected Albedo's ascension. The Black Testament's E.S., Dan attacks Shion while she escapes from the Dämmerung. Later in the game, the Testaments arrive at the Ω System and kill Sergius XVII. Ziggy recognizes the Black Testament as Voyager and attempts to kill him to no avail. The Testaments are later seen in the ending, welcoming the new White Testament with their master, Wilhelm.

Characteristics
Testaments wear full body armor and wing-shaped cloaks. The color of their armor depends on the individual. They also conceal their faces with bird-shaped masks. Testaments can also survive the vacuum of space without proper equipment.

Blue Testament
The Blue Testament is a A.G.W.S pilot, Luis Virgil. He became a Testament after being killed by the KOS-MOS while fending off a Gnosis attack on the Woglinde.

Black Testament
The Black Testament is a cyberterrorist, Erich Weber, also known as Voyager. He became a Testament after being invited by Wilhelm to become a Testament and is the oldest Testament.

Red Testament
The Red Testament is former Vector Industries's chief engineer, Kevin Winnicot of the KOS-MOS project. He became a Testament after being killed by the KOS-MOS archetype.

White Testament
The White Testament is the immortal U.R.T.V., Albedo Piazzolla. He became a Testament after being killed by Jr. in the Space-Time Anomaly and is the recent Testament.

Trivia

 * The Testaments are very similar to the Consuls from Xenoblade Chronicles 3.
 * Both are humans who were revived after their deaths by a higher being to serve them.