The Age of Exploration could be another good setting. Connor could board ships and travel to new lands. He would face new enemies, such as pirates, and might also discover ancient assassin secrets hidden in far - off places.
A third idea is that Connor time - travels to a post - apocalyptic world. Here, he has to use his survival skills and assassin training to help the remaining survivors. He could also try to find a way to restore the world to its former state, all while facing new and dangerous threats.
One great Connor Kenway fanfiction is 'The Hidden Path'. It delves deep into Connor's character, exploring his internal struggles as he tries to protect his tribe and the colonies. Another one could be 'Connor's Redemption', which shows a different side of his journey, focusing on how he copes with the consequences of his actions. And 'Connor Among the Ancients' is also interesting as it places Connor in various historical and mythical situations.
Begin by creating a conflict that involves both Edward and Connor. It could be a new Templar threat that has roots in Edward's time and resurfaces in Connor's. Develop their characters further by giving them internal struggles. Maybe Edward is haunted by his past actions as a pirate, and Connor is struggling with his identity as an Assassin in a changing world. As you write, keep the pacing right. Alternate between action - packed scenes and more reflective moments. And most importantly, let your love for the Assassin's Creed series shine through in your writing.
A fanfiction could be about family ties. Maybe Connor discovers he has a distant relative who was part of Edward's crew. He sets out to find this person and in the process, uncovers more about his family's past. Along the way, he meets Edward's ghost or some kind of spiritual manifestation of him. Together, they work to protect a hidden Assassin stronghold from the encroaching Templars.
Altair Ibn - La'Ahad would be an excellent choice. Since they are both from the Assassin's Creed franchise, it would be interesting to see how their different time periods and experiences shape their interactions. Altair's more traditional Assassin ways could contrast with Connor's more nature - influenced style.
One possible plot could be that Connor, being from a later time in the Assassin's Creed timeline, stumbles upon some ancient records or a hidden memory that leads him to Edward. They might initially be at odds due to their different time periods' ways of life. Edward, being more of a swashbuckling pirate - assassin, could teach Connor some new combat techniques or ways of navigating the high seas that Connor hadn't experienced in his mainly land - based adventures. They could also bond over their shared goal of fighting the Templars, with Edward sharing his experiences from the earlier days of the conflict and Connor bringing in his knowledge of the more evolved Templar plans in his time.
A great place to find Connor Kenway fanfiction is Archive of Our Own (AO3). It has a large collection of fanfictions across various fandoms, including Assassin's Creed with many dedicated to Connor. Fanfiction.net is also a good option. It has been around for a long time and has a decent amount of Connor Kenway fanfics.
A new villain could be introduced in the fanfic who is specifically out to get Connor Kenway. This villain might have a personal grudge against Connor or be on a mission to eliminate all the Assassins, and Connor becomes their prime target and ultimately falls to their schemes.
His relationship with his friends could change significantly. For example, if he travels back to a time when they were younger, he might be more protective of them. He could also inspire them in different ways, leading to stronger bonds. His relationship with his sensei might also be affected. He might be able to offer new insights based on his future experiences.
One great DBH Connor time travel fanfiction is 'Connor's Time - Warped Adventure'. It takes Connor to different points in the past of the Detroit: Become Human universe and shows how his presence alters events in really interesting ways.