User blog comment:FairyRaven/Fairy Tail Chapter 390: The Story of a Boy, Review and Commentary/@comment-70.208.141.47-20140627171538

He explains how is body is intact and even shows it. He used Hell's Core to put his body together. You know Hell's Core, the facility Mirajane fucked up good. As for how he knows Natsu, don't forget that Natsu is well known across the world as Salamander, and that he's famous in the Balam Alliance