Absalom's Legacy Virus infection was revealed in X-Force (1st series) #37. He died at Selene's hands in X-Force (1st series) #54, and again in Cable (1st series) #154. Each time, he returned due to his status as an External.
In X-Force #37, Absalom related a story where he killed the legendary gunfighter Caleb Hammer in 1896, revealing his mutation seemingly for the first time. However, Absalom also appeared with the Externals in 1891, Gambit (3rd series) #14, already ascended. The man who shot Caleb Hammer was identified as Corey Flynn in the Marvel Westerns Outlaw Files.