The Witch Queen told Asta and his friends a bit about the history of the elves in Black Clover Episode 65. She stated that the elves possessed great magical abilities and were so strong that many of them were her equal in terms of magical strength (and she is very prideful; for her to admit that says a lot.)
What is really baffling me thou is when she stated that the leader of the elves was the former wielder of the Anti-Magic weapons that Asta currently uses, which subsequently blew Asta's mind and mine too!
How is it possible if people with Magic can't wield them? We know that the only reason that Asta can use those swords is because he was born without magic and hence the sword does not weaken him. However, the leader of the elves possessed strong magical powers and yet he could still wield the Anti magic weapons. Even the Wizard King admitted that only people without Magic could wield those weapons. Are there any exceptional rules to how the Anti magic weapons work?