User blog comment:FairyRaven/Fairy Tail Chapter 399: Wings of Despair, Review and Commentary/@comment-24066070-20140908130106/@comment-24066070-20140908170800

On Tenrou, he was a Dragon and likely just wants to kill whatever he sees, since he deems it irrelevant and doesn't bother to check each individual.

In the case he would be returned to a human state, he may be forced to interact with those present and thus find out there are Dragon Slayers among the rubble of Plutogrim.