Read more about Abyss at: Wikipedia

Official Site: Marvel

Abyss (Nils Styger) is a fictional character, a mutant in the Marvel Comics Universe. An alternate universe's counterpart of the character first appeared in X-Men Alpha, and the heroic Marvel Universe version of the character first appeared in Cable vol. 2, #40.

Nils Styger first appeared as a protector for Genosha researcher Renee Majcomb, whom he had been assisting with research into the Legacy Virus from which Abyss suffered. However, he did not die due to the actions of Colossus, who sacrificed himself to release an airborne cure to the virus which had taken his little sister Illyana's life several years prior.

Abyss was later seen in Berlin, Germany battling the former Gene Nation member known as Fever Pitch. Both mutants were captured by Banshee's mutant militia known as the X-Corps. While being held by the X-Corps, Abyss witnessed Sunpyre's murder. When the terrorist Mystique revealed herself and her intentions to use the X-Corps, the wounded Banshee freed Abyss from his confinement. Abyss then sucked Mystique through his interdimensional void, and, unable to shut off his power, almost swallowed Banshee also. The timely arrival of some other members of X-Corps stopped that however. Abyss admitted that he had no idea where Mystique was transported to or if she would ever return.

Abyss later resurfaced when his father Azazel psychically summoned his many children to attempt to release his army from the Brimstone Dimension that he had been banished to hundreds of years before. In an attempt to loose himself and his comrades, Azazel had traversed the dimension barrier many times and sired children in the hopes that one of them would be able to breach the dimensional barrier. Abyss joined forces with the X-Men to avert Azazel's attempt to bring his army into Earth's dimension and succeeded in foiling his father's efforts. He was subsequently revealed to be Nightcrawler's half-brother, as both were sons of Azazel.

Abyss has not been a contender in any CBUB matches.