Who could be the possible attacker in the 'rito gets stabbed fanfiction'?

Another possibility is a character who has been possessed by an evil spirit. They may not be in their right mind when they stab Merlin. This could add an element of mystery as Merlin has to figure out not only who stabbed him but also how to exorcise the spirit from the person's body.

I'm not sure specifically as there could be many different interpretations in such a fanfiction. It might involve a character named Rito facing a stabbing incident, perhaps in a battle, a crime scene, or a situation of betrayal.

It might be a jealous rival. If Sakura is popular or has something that others envy, like a special talent or a relationship, a rival could have stabbed her out of envy.

It could be an old enemy of Nicole's from her police work. Maybe someone she put in jail before who has a vendetta against her. This person might have been released recently and is out for revenge.

Another character who has a personal vendetta against Clary or her family. For example, a jealous rival or someone who blames her family for past misfortunes. This would add a layer of drama and personal conflict to the fanfiction.

It could be a jealous rival duelist. Someone who has always been in Kaiba's shadow and saw stabbing as a way to eliminate the competition.

It could be a jealous gamer. Someone who has been envious of the Game Shakers' success and sees Hudson as an easy target to get back at them.

Well, in some 'Peter Parker Gets Stabbed' fanfiction, it might happen during a fight with a new, powerful villain. The villain could have a weapon specifically designed to harm Spider - Man, like a blade coated with a substance that weakens his healing factor. Peter might get stabbed while trying to protect someone, like MJ or Aunt May. And then he has to deal with the injury, hiding it from his loved ones while also trying to figure out how to defeat the villain before the wound becomes too much to handle.

Perhaps Sakura's injury makes her realize she has some hidden strength within her. She could start to have visions or gain new abilities while she's recovering from the stabbing. This could then lead to a whole new arc in the fanfiction where she has to learn to control these new powers.

Morgana could be a likely antagonist. She has been at odds with Merlin in the series and has her own motives and powers. She might see stabbing Merlin as a way to further her plans against Camelot or to eliminate a threat to her own power.