User blog comment:PUNCHURPREGNANT/Gray and Silver Predictions/@comment-1776824-20140112194221/@comment-7418318-20140112215201

Jellal being manipulated by Zeref was also by a very reliable source at the time, as was Carla having the mission to kill the Dragon Slayers and Fiore going to be invaded by 10.000 Dragons and there being a need for turning the Eclipse into a cannon among others.

Just because Cobra said so, doesn't automatically make it the absolute truth and the other arguments you gave only proof that he is a Demon now, but say nothing about how he became one.

He certainly stands out among the 9DG because all the others so far have only shown their curse, but he alone has Devil Slayer Magic.