User blog comment:Vazelos3/In Marshall's shoes/@comment-5640399-20131014003437/@comment-9787781-20131014033803

Its my personal belief that Shiryu already has a devil fruit, the Logia of Rain and it was the double combination of Magellan's poision and the Shiryu being close to invulnerable because of the Logia and his ability with the sword (for anyone who had haki) that made Impel Down inescapable.