6(Black Clover)

An Au where after the elf resurrection arc or at least after Asta joins the Black Bulls, the King and other nobles start making people doubt the magical squads to the point they push them away.

With people not trusting them and making their jobs more complicated by it, even Julius influence couldn't help them as they noticed too late what the king and nobles were doing.

While most squads were simply going to just deal with it, the Black Bulls wouldn't take this treatment and decided that if the people believed they didn't need them then they could leave.

Cue the Black Bulls disappearing completely(they moved to the neutral zone) with some of their families and close friends following them(Finesse, Magna's family, Asta's orphanage, etc).

It didn't take long for Golden Dawn to follow the Black Bulls as even the nobles from the squads were done with everything(and the influence of William, Langris, Mimosa and Yuno was big and they couldn't deal with having their closest family/friends so far).

Slowly the other squads joined the Black Bulls in the Neutral Zone and Julius after recruiting a few people that still wanted to be part of the magic squads also followed the, leaving the Clover Kingdom defenceless.

What would this mean for canon? Clover may still be targeted by Spade and would quickly be defeated as they didn't have protectors, not all nobles agreed with the king's plan but those who did were all from all families(there are a few Silvas, Vermillions, etc and Ledior and Lilliane are also part of the group who agrees with the king...they wanted Langris to quickly marry Finesse so they could have more power), the squads would all go through a rigorous training to deal with the high mana zones besides maybe have them all travel through other kingdoms(Henry made his mansion bigger so all squads could live in it and everyone was happy to offer their mana to help him) so they could still train in Hearts and maybe even travel to Hino.

What about Lucius, Conrad, the Triad, etc? It would be up to the writer but they certainly would make the job even harder for the villains(especially as Henry enforced that everyone should go to therapy to try and reduce the damage that may be done to the mansion so the Vaude-Roulacase and Silva siblings have a much better relationship and all that)..