Anime Crossover: The System Helps Me Save the Ones I Can’t Let Go

(Some plot points may be out of character, and there are many personal interpretations.)

Lin Qiqi watched Akainu punch straight through Ace's heart.

Demon Slayer had become Pillar Slayer.

Sirius, Regulus, Severus, and the Weasley Twins all sacrificed themselves.

Lin Qiqi thought: If only I could go to their worlds and save them. A flash of white light, and her wish came true.

P.S. A crossover transmigration story. The heroine may have a romantic pairing. The main worlds are Pirate King, Demon Slayer, and Harry Potter. The heroine has a golden finger, a System, and can only gain skills by completing missions. (Bonus chapter: A special Detective Conan story about saving the police academy team.)

This is my first time writing a story, so please forgive my writing if it's not very good.