User blog comment:FairyRaven/Fairy Tail Chapter 324: The One Who Closes The Door, Review and Commentary/@comment-112.205.41.120-20130323032321/@comment-4829046-20130323074929

Apparently Demons can be created from any kind of matter, so I don't think he needs to actually plan anything. He could just arrive suddenly and create an army out of the buildings, elements etc.