What are some unresolved mysteries in Fairy Tail?

Hello,

I am not certain if these count as unresolved mysteries, but the full extent of Ivan and God Serena's powers were never revealed.

Arlock's face was never shown, nor was his reason for wearing a mask ever revealed.

It was never revealed if there were devil slayers of elements beyond ice.

I suspect that Mary from the Avatar arc may possibly be the same Mary from the prequel series Fairy Tail: Ice Trail (mainly because both of them seemed to be infatuated with Gray), but Mashima has never commented on that.

On that subject, the ultimate fates and whereabouts of Gray's companions from that series during the present storyline were never revealed.


I didn't find the right solution from the internet.

Hello,

The Bureau of Magic Development has done much good, and bad, in the past. It has recently come under new management. This new management has a new goal as well: the domination of all magic in all forms.
This arc will require participants to be separated into two groups. Those deemed 'threats' by the Bureau will be kidnapped, with no choice in the matter. Everyone else will have to prove the Bureau wrong and come to rescue their friends. There will be no shortage of fights, as well as brain stumping puzzles and false hope, and some radical prizes for those who participate (Is a baby dragon on the line? Maybe.)

This is not spam? I haven't watched Fairy Tail, but I have friends who watch it.

---

You did not answer, so I deleted the links. It's like spam.