Aegis

An Aegis is a type of in Xenoblade Chronicles 2. They are especially powerful Blades created by the Architect.

Characteristics
Aegises have all the characteristics of other Blades: they have a Core Crystal on their chest and use it to manifest a weapon to their Driver to fight alongside them in battle. However, they are notably more powerful than any normal Blade, and are unique in several other ways. The most noticeable is their Core Crystal: it is shaped like a cross and a colour other than blue, both of which are the main way for the general public to identify them as special. Aside from the Core Crystal, they are entirely indistinguishable from a normal human in appearance, continuing the pattern of stronger Blades appearing more human. Aegises can themselves be Drivers of other Blades, something which it is unknown whether a normal Blade can do. Aegises also contain the knowledge and data of all other Blades, allowing them to restore minor damage to Core Crystals. Uniquely, Aegises do not return to their core upon their Driver's death. Being Blades born of resonance with a human and a Trinity Processor Core, they are capable of controlling Artifices at will, provided their Core is not damaged. They can also survive with a damaged core, at the cost of their power, and can even live a short time completely deprived of their core, as stated by Malos and as shown by Pneuma.

There are only two Aegises in the world of Alrest: Mythra, who can swap forms between herself and Pyra, and Malos. Both are known as "the Aegis" at varying points of Alrest's history, as their goals and whims reshape the known world with ease. This is due to only two Trinity Cores remaining within the physical Trinity Processor aboard Rhadamanthus Spaceport; Logos and Pneuma, and both were instantiated into Blades by humans living in Alrest.