The potential consequences are huge. Since Adrien has relationships with many people in Paris, he could use those connections to his advantage as Hawkmoth. He might target the families of the heroes or people close to them. This would not only put physical danger on the city but also emotional stress on the people. The trust that the Parisians have in the heroes might also be shaken as they wonder how someone like Adrien could turn into a villain.
Paris would be in chaos. With Adrien as Hawkmoth, he would know a lot about the heroes, especially Ladybug. So he could target them more effectively. There would likely be more akumas, and they might be stronger and more difficult to defeat.
The city would probably become a darker place. Hawkmoth usually preys on people's negative emotions. If Adrien is Hawkmoth, he could manipulate the emotions of the Parisians more subtly as he knows them well. This could lead to a breakdown in the community, with people turning against each other more often. Also, the economy could suffer as businesses would be affected by the constant attacks.
On a personal level for Adrien, he would be straying from his own moral compass. He has always been a character associated with good and helping others. By helping Hawkmoth, he would be going against his own values, which could lead to internal conflict and a possible downward spiral in his character development. He might start to question his own identity and the choices he has made, and it could take a lot of effort to get back on the right track.
If Adrien were Hawkmoth in fanfic, it could change the dynamics of the story completely. It might explore his internal conflicts and the impact on his relationships with other characters.
Well, it could be that some dark magic or a powerful artifact corrupted him over time. Maybe he faced a great loss or betrayal that led him down this dark path. For example, if Ladybug was somehow lost or turned against him, it could have been the final straw that made him embrace the role of Hawkmoth.
Perhaps Adrien becomes Hawkmoth because he's been pushed to the edge by Ladybug's rejections. As Chat Noir, he's constantly in love with her but feels unappreciated. The pain of this unrequited love could twist his perception of good and evil. He might think that if he were in control as Hawkmoth, he could make Ladybug see him in a different light. He could use the power to create situations where Ladybug has to rely on him more, or at least understand his pain.
He'd probably face a lot of hostility. People might avoid him or even try to attack him.
One common theme is self - discovery. Adrien often discovers new aspects of his powers or his own strength during the fight with Hawkmoth.
One implication could be that it might strain their friendship a bit. If Adrien really believes this in the context of fanfiction, he might start to act differently around Nino.
If Adrien becomes Hawkmoth in fanfiction, Paris would be in for a major shock. His friends, like Nino and Alya, would never suspect him at first. And Marinette, who is Ladybug, would be facing a completely different kind of enemy. She's used to fighting Hawkmoth as this unknown figure, but now it's someone she knows so well. It would change the dynamic of their battles entirely.
Maybe Adrien noticed some strange behavior from Nino that seemed similar to what he imagined Hawkmoth would do in fanfiction.
One possible reason could be that Marinette has been acting strangely in ways that seem to Adrien to be related to Hawkmoth. Maybe she has been seen in places or at times that are suspicious, like near akuma attacks or where Hawkmoth might be operating from. Another reason could be that someone has been spreading false rumors about Marinette, leading Adrien to believe she has some connection to Hawkmoth.