So the most recent chapter confirms that the working theory as to why a person can't eat two devil fruits is wrong. There is no devil inside. So we have no explanation at all. My theory as that you actually can eat multiple devil fruits. The only person we ever saw try to eat a second devil fruit was fine, and actually obtained a second power. Maybe the world government spread this lie in order to prevent people from gaining too much power, but Im and maybe the gorosei actually have multiple devil fruits. Maybe there's nothing special about Blackbeard that allows this, it's just that he knows the truth. Thoughts?