Onyxx

Onyxx
Publication information
Publisher	Marvel Comics
First appearance	X-Men, vol. 2 #171 (August 2005)
Created by	Peter Milligan (writer) Salvador Larroca (artist)
In-story information
Full name	Sidney Green
Species	Human Mutant
Team affiliations	Chevaliers training squad[broken anchor] Xavier Institute X-Men-In-Training
Abilities	Superhuman strength and durability

Onyxx (Sidney Green) is a fictional mutant appearing in comic books published by Marvel Comics. He first appeared in X-Men, vol. 2 #171 (August 2005), and was created by Peter Milligan and Salvador Larroca.

As a child, Sidney Green lived in various foster homes and orphanages, unable to find acceptance because of his crude behavior and chronic bedwetting.^[1] This was cured after his mutant abilities activated, transforming him into a four-eyed golem-like creature.

Subsequently, Sidney becomes a student at the Xavier Institute as Onyxx and joins Gambit's training squad, the Chevaliers.^[2] He develops a crush on fellow student Foxx, who is later revealed to be a disguised Mystique.^[3]

Sidney is one of 198 mutants who retain their powers after the Scarlet Witch depowers most mutants on M-Day.^[4][5][6][7] He is later killed by Wither before being resurrected after the establishment of Krakoa.^[8][9]

Onyxx has a craggy granite body, which gives him superhuman strength and durability. He also possesses an additional pair of eyes, but it is unknown if these serve any special purpose.