There's also the possibility that it's a member of a rival group in the town. If there are different factions vying for power or control, they could see Nicole as a key figure in the group that opposes them. Stabbing her would be a way to weaken that group and send a message.
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.
It could be a group of out - of - town bounty hunters. They might have heard about Nicole's reputation as a tough cop and see her as a valuable target to bring in for some kind of reward. Maybe they are working for a shadowy figure who wants Nicole out of the way so they can take over the town's law enforcement.
Nicole's family members could also be involved. Maybe her sister or mother sees the hickey and has a strong reaction. They might be shocked, concerned, or even happy depending on their view of Nicole's relationship. And this could lead to some interesting family - relationship - based plot developments in the fanfiction.
One possible plot could be that Nicole is attacked while on a solo mission to gather information for the resistance. She manages to fight back briefly but is overpowered. Then Waverly races to her rescue, using her own skills and the power of their love to overcome the attackers.
Well, it could be about Nicole getting a hickey and then trying to hide it from others in their small town where everyone knows everyone. Maybe she's worried about what her family or friends will think, especially if she's not ready to fully disclose her relationship yet.
Another scenario could be that Nicole gets stabbed while protecting Waverly. This causes Waverly to feel guilty and determined to become stronger to protect Nicole in the future. The fanfiction could then focus on Waverly's journey to gain more power or knowledge, while also showing Nicole's slow but steady recovery and the deepening of their relationship through this difficult time.
It could be an old enemy of Ezra. Maybe someone from his past who has a grudge against him for some reason, like a business deal gone wrong or a personal feud.
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.
Another plot could involve Nicole getting handcuffed during a dangerous mission. She has to rely on her wits and the help of her friends, especially Waverly, to get out of the situation and complete the mission successfully.
Well, in a fanfiction plot, Nicole could be hurt while trying to protect her partner. For example, if there's a bomb threat in a building where they are. Nicole would shield her partner from the blast, resulting in her getting seriously hurt with burns and fractures. Or perhaps she gets into a car accident while rushing to a crime scene because of a mechanical failure in her vehicle.
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.