Esse é provavelmente o evento cruzado Projeto Purgatório que apareceu pela primeira vez em New Mutants Vol 3 # 9 (março de 2010). Os soldados eram uma equipe de agentes militares geneticamente melhorados sendo enviados para investigar o reino místico do Limbo onde eles permaneceram presos pelo que pareceriam para eles 26 anos. Os eventos duraram sete aparições e foram encerrados em New Mutants Vol 3 # 21.
Da Marvel Wikia:
Following the Inferno, the United States Army founded Project Purgatory to research the fields of the supernatural and paranormal. One of the recruited scientists, Doctor Noc, developed technology to use the X-Gene-Positive infants N'Astirh kidnapped and the New Mutants and X-Terminators delivered to them to open portals to Limbo. General Ulysses, Doctor Noc, and a trained band of military soldiers established a military base in Limbo, the Hatchery. At the base, they continued to experiment, both on demons and on the Inferno babies, and train new soldiers. However, when they recovered the Bloodstone amulet, the base was attacked by Witchfire and the Inferno babies were believed dead. The Earth based military forces sealed off the portal Epsilon, leaving those on the Limbo base stranded to find the observation portal with virtually no hope of escape.