Tatsumi is likely the main character in the story named 'The Push Man'. He might be someone who is involved in a pushing - related job, but we don't have more details without reading the actual stories.
One common theme could be the idea of power and growth. Both Naruto and Tatsumi have their own paths of becoming stronger in their respective stories. So in fanfiction, it might be about how they help each other grow in power in a new situation. For example, Naruto teaching Tatsumi some ninja techniques and Tatsumi showing Naruto her own combat skills.
Tatsumi would likely react with defiance. He's a brave character and wouldn't easily submit to Esdeath's kidnapping. He might try to fight back right away if he has the chance.
Well, in general fanfiction, Tatsumi is often depicted as brave and kind - hearted. But in lemon fanfiction which we should avoid due to its inappropriate nature, if any such exist, it might distort these characters in an improper way. Mine is usually seen as strong - willed, and in normal fanfiction she has great chemistry with Tatsumi in terms of their personalities.
There are a lot of factors that can make a 'naruto and fem tatsumi' fanfiction great. It could be the way the author develops their relationship, whether it's a friendship or something more. Also, the plot needs to be engaging. For example, they could be thrown into a strange dimension where they have to rely on each other to get back home. The world - building in these fanfictions can also be really cool, like combining elements from the Naruto universe and Tatsumi's world.
Tatsumi might also face opposition from his friends and allies. They would likely be very suspicious of Esdeath and not understand why Tatsumi is falling for her. His friends could try to convince him that she's not good for him, which would put a strain on his relationships with them as well as his new - found feelings for Esdeath.
Yes, unfortunately, Tatsumi met his end in the manga. His death was a crucial event that influenced the direction of the narrative and the fates of other characters.