Well, a great storyline might involve Fem Naruto being mistaken for a new type of devil or some sort of mysterious being in the Highschool DxD world. As she tries to clear up the misunderstanding, she gets drawn into the complex politics between the different factions. She could also have a rivalry with some of the more powerful female characters in the DxD world, like Rias, which would lead to some intense and exciting battles.
One interesting storyline could be Fem Naruto joining the Occult Research Club in the Highschool DxD universe. She could use her ninja skills, like her shadow clone jutsu, in unique ways during club activities or battles against devils and fallen angels. Another could be her forming an unexpected friendship with Issei, perhaps teaching him some ninja stealth techniques which come in handy during his escapades.
A possible storyline is that Fem Naruto has a special power that is coveted by the various groups in Highschool DxD. This power could be related to her chakra, which is something entirely new in that world. As she tries to protect her power and herself, she teams up with some unlikely allies from the DxD universe. Maybe she uses her Naruto - like determination to inspire those around her, including some of the more jaded characters in the DxD world, to fight for what's right.
A practical answer is Chapter 223, because it turns the idea into a concrete scene. The chapter opens with So, for the first time, Jiang Yan, who had always styled himself as the..., adds pressure through He could simply have someone send a flurry of gifts and make some..., and ends on The damned.
The best chapter pointer here is Chapter 268, "I'm Just Jealous of Jiang Li, I'm Annoyed by Her!". It opens with To ensure the company's successful listing, Shen Lan even went so far as... and closes on Jiang Li has nothing to do with Director Sun!" "Because she is my niece!"....
A practical answer is Chapter 225, because it turns the idea into a concrete scene. The chapter opens with When Zhao Lang's devastatingly handsome face appeared, all six people..., adds pressure through Alright, it's about time, let's officially get started., and ends on Which big shot is.
If you want the clearest chapter reference, go to Chapter 245. Early on, Jiang Yan became even more smug upon hearing this.; later, the chapter leans on Oh, only thinking of your dear brother when you've got nowhere to stay?.
Look to Chapter 263 for the clearest answer. It begins with Southwest Wildlife Protection Association V: On the evening of July 10 of..., keeps building through They discovered dozens of severely injured and dead wild animals,..., and lands on But when she saw Wen Jiaojiao and Qi Tianyu and others.
Look to Chapter 223 for the clearest answer. It begins with So, for the first time, Jiang Yan, who had always styled himself as the..., keeps building through My good little sister, I'm begging you, help me figure out how to avoid..., and lands on The damned Jiang Li was tricking him again!.
A practical answer is Chapter 217, because it turns the idea into a concrete scene. The chapter opens with But Director Sun didn't plan to give her any room to think, he directly..., adds pressure through But," Director Sun took over the conversation, "since you chose the wrong..., and ends on.
Chapter 230 is the strongest chapter-level answer because it starts from Shang Shaojing's expression wasn't looking too good either. and follows through on If he knew that your stepmother was secretly prompting you towards a.... The payoff is that the chapter closes with "Liu Linmei!
If you want the clearest chapter reference, go to Chapter 226. Early on, What was all that before then?; later, the chapter leans on Jiang Li quickly tapped the screen twice, and a red packet link that was....
A practical answer is Chapter 267, because it turns the idea into a concrete scene. The chapter opens with Jiang Li had just turned around when she was suddenly embraced by a..., adds pressure through Although she later faced unprecedented public pressure and her career hit..., and ends on.