"EXyz" an abbreviation of "Energy Xyz", abbreviated "EX" Enerugī Ekushīzu), is an Archetype of monsters that can be Xyz Summoned by Chaos Xyz Evolution, with the effect of "Hyper-Rank-Up-Magic Amplification Condenser". They have been primarily used by Catherine Miller in her Deck. These monsters are created through the elemental power of LIGHT to improve Rank 1 and 2 Xyz Monsters.
Xyz Materials attached to "EXyz" monsters resemble swirling spheres with smaller motes of light around them, and are called "Atomic Xyz Materials". Like monsters that can utilize Chaos Xyz Evolution, these monsters require an additional Xyz Material but with 10 higher Levels in a regular Xyz Summon, since they themselves are 10 Ranks higher than their respective original counterparts.
"EXyz" monsters are shown as being in some sort of starry landscape, with various stellar phenomenon, like suns, planets, and galaxies, behind them. Furthermore, all "EXyz" monsters are primarily composed of energy, with armored portions resembling their old selves forming the shell around them. In juxtaposition to the "CXyzs'" glowing red lines, "EXyz" monsters have white energy making up most of their form.
Due to their connection to the very low Ranks of Xyz Monsters, the "EXyzs" are much more powerful than a normal Ranked Up Xyz Monster, representing Catherine's drive to protect the weak with her own monsters. Because of this, "EXyzs" form a perfect counter against the Barians and their "CXyzs".