X-Nation 2099
X-O Manowar
Xorn
Xorn (AgeOfApo)

Gender: ♂
Alternate version of: Xorn
Universe/Dimension/Timeline: Earth Age of Apocalypse (Earth-295)

Xorr the God-Jewel
X-Patrol

Alternate version of: X-Men I
Universe/Dimension/Timeline: Earth Amalgam

Xraven

Gender: ♂
Clone/Copy/Impersonator of: Kraven the Hunter
Created by: Mister Sinister
Powers taken from: Angel I, Beast I, Cyclops I, Iceman I, Marvel Girl I

Features
Heroic Age: Villains 1.FT
X-Men Earth's Mutant Heroes 1.FT

X-Ray
X-Sentinels
X-Statix
X-Terminated
X-Terminators I
X-Terminators II
X-Ternals (AgeOfApo)
X-Treme

(Adam X)
Created by: Fabian Nicieza, Greg Capullo, Jeff Johnson
Gender: ♂
Parent(s): D'Ken Neramani

Features
Marvel Legacy: The 1960s-1990s Handbook TPB 1.FT
Marvel Legacy: The 1990s Handbook 1.FT
X-Men: The Ultra Collection 4.FT

X-Treme Sanctions Executive (X.S.E.)
X-Treme X-Men I
X-Treme X-Men II