If Asta lost someone very close to him, like Yuno, and he believed that the Magic Knights or the kingdom could have saved Yuno but didn't because of their negligence. This heartbreak could turn him against the establishment. He might start to see the world in black and white, believing that anyone associated with the kingdom is bad. His actions to seek revenge would then be seen as 'evil' as he goes against the order of the Clover Kingdom.
One way Asta could turn evil in a fanfiction is if he was constantly ostracized for his lack of magic in a more extreme way. For example, if the Magic Knights not only rejected him but actively bullied him. This could lead to a build - up of anger and resentment. Eventually, he might decide that the system that has shunned him is wrong and needs to be overthrown, leading him down an 'evil' path of using his anti - magic to cause chaos rather than protect.
A potential plot could be Asta's slow descent into darkness. He starts off as a bit more cynical after facing continuous rejections. Then, he meets a group of outcasts who have also been wronged by the system. They convince him that the only way to make things right is to take power by force. Asta begins to use his anti - magic to steal magic from other mages, believing it's a way to level the playing field. As he does this, he becomes more and more feared and is seen as a threat to the kingdom.
Well, he might bring a whole new level of energy. His never - give - up attitude could inspire the Blue Roses. Maybe he'd teach them some of his unique combat moves. And his anti - magic power could be a real game - changer in their battles.
He might bring a new dynamic to the group. His unique anti - magic abilities could be a great asset in battles that the Blue Rose gets involved in. Maybe he would also change the internal relationships within the group, as he has a very determined and positive personality.
Well, if Asta is kidnapped in a fanfiction, it could be a plot by some anti - magic group who see Asta's anti - magic as a threat. His sword might be taken away from him too. But Asta being Asta, he would try to fight back even without his sword. His determination would inspire any captives around him to also rise up against their captors. His friends would soon figure out who took him, probably through some detective work by Finral's spatial magic or Gauche's mirror magic.
They could embark on an adventure to find a hidden magical artifact. This artifact could be said to have the power to enhance one's magic abilities even further. Asta would be eager to get it to become stronger and prove himself, while Vanessa would be more cautious but still go along to support her friend.
It could begin during a mission. Asta is separated from the rest of the Black Bulls. While he is alone, a strange magic spell is cast upon him that renders him unconscious. When he wakes up, he finds himself in a dark, damp cell. He realizes he has been kidnapped. The kidnappers could be a group of rogue mages who want to use Asta's anti - magic for their own evil purposes. They start to perform experiments on him to try and understand his power better.
One idea could be a story where Asta and Vanessa go on a special mission together. They face a powerful enemy and have to rely on each other's unique abilities. Asta's anti - magic sword combined with Vanessa's thread magic could create some really cool battle scenes.
Well, perhaps Asta could be corrupted by a powerful dark magic artifact. He might start to see his friends as obstacles in his quest for power and turn against them.
Fanfiction about a female Asta in Black Clover can be really interesting. It allows for a different take on the story. Writers might explore how a female Asta would handle the challenges in the Clover Kingdom, like the Magic Knights entrance exam. Maybe she'd have a different dynamic with Yuno, perhaps more of a sisterly bond. It could also show how she'd deal with her lack of magic in a unique way compared to the male Asta in the original story.
Asta's age in the Black Clover story arc changes over time. At the beginning, he's around 15 years old, and as the story goes on, he gets older. The exact age depends on the particular events and chapters.