Well, Choso is a really interesting character in Jujutsu Kaisen. His backstory is full of mystery and tragedy, which gives fanfic writers a lot of material to work with. People are drawn to exploring more about his character, his powers, and his potential relationships in fanfics.
Sure. One great 'choso jjk fanfic' is 'Choso's Redemption'. It focuses on Choso's journey to find his place in the Jujutsu Kaisen world after all the chaos he has been through. The story delves deep into his character, exploring his relationships with other characters in a very interesting way.
For a High School DxD and JJK fanfic to be great, it should have well - developed characters. In High School DxD, the characters have distinct personalities like Issei's pervy yet determined nature. In JJK, Yuji's growth and his complex relationships are important. A good fanfic will build on these traits.
The exploration of the two different worlds is really engaging. The post - apocalyptic, walled - in world of AOT and the hidden jujutsu society of JJK are so different. When combined in a crossover, it allows for new storylines. For instance, how the JJK characters would adapt to the constant threat of Titans and how the AOT characters would react to the existence of cursed spirits.
There's also 'Jujutsu and Bungo in an Alternate Realm'. This fanfic delves deep into how the powers from both universes would interact. It shows the characters trying to understand each other's abilities and form alliances. It's a long read but definitely worth it for fans of both series.