One interesting concept could be a crossover with a fantasy world like Middle - earth. Imagine an assassin having to navigate the perils of Mordor while still maintaining their creed. Another concept might be a crossover with a historical event not directly related to the main Assassin's Creed timeline, such as the sinking of the Titanic, where assassins could be on board for a secret mission.
Writing a good Assassins Creed crossover fanfic is all about balance. You have to balance the elements of Assassin's Creed, like the hidden blade and the assassin's parkour skills, with the elements of the crossover. Let's say it's a crossover with a detective story. You can't overshadow the detective's investigation skills with the assassin's combat abilities. Also, create believable relationships between the characters. If an assassin teams up with a detective, there should be some initial mistrust that gradually turns into respect and cooperation as they work towards a common goal.
Agent 47 from the 'Hitman' series is extremely dangerous. He can blend into any environment, use a wide variety of weapons and methods to eliminate his targets without being detected. His cold - blooded and calculating nature makes him a top - tier assassin.
There was this time when I entered an old abandoned house in Skyrim. I expected to find some treasure or a spooky enemy. But instead, there was a group of skeevers (the rat - like creatures) having a little party. They were all huddled around a small piece of cheese and they looked so cute and out of place. It was a very unexpected and funny discovery.
I was in a tavern in Skyrim and decided to challenge a drunk Nord to a drinking contest. I thought my character could handle it. But after a few rounds, my character started staggering around and seeing double. Then he passed out right on the table, and the Nord just laughed his head off. It was a really funny experience.