How did Asta's mom even get pregnant if she has that aura? Imo, this means Asta's father is either manaless and stupid or has an absurd amount of mana and lifeforce such as an elf does.
Depending on if Asta's devil is a few years older than him, it's possible that Asta's mom actually met the guy who dropped Yuno off. An important piece to this is that the guy seemed to have died or been injured for an unknown reason between when he located the church and when he actually sent Yuno there with his spell. It could be that he began to die because Asta's mom was near, and Asta's mom later took the 5-leaf the grimoire off his body.
Another bit to this is that he found Yuno's magic stone, which is tied to Licht, while in the magic zone, so it's not too farfetched for him to have also stumbled upon the 5-leaf grimoire. Alternatively, it's also possible Asta's mom frequently wandered the mana-zone and found his body & possessions there or the book on her own.
