One common theme is protection. Accelerator is often depicted as protecting Last Order from various threats in the fanfics. Since he has a sort of guardian - like relationship with her in the original work, this theme builds on that dynamic.
One common theme could be protection. Given Accelerator's power and his complex character, he might be seen as a protector of Last Order. Another theme could be friendship evolving into something more, as they interact more in the fanfic stories.
I really like 'The Protector's Promise'. It focuses on Accelerator's unwavering commitment to keep Last Order safe. The story has some great action scenes where Accelerator shows off his amazing powers while shielding Last Order.
There are a lot of emotional arcs that can be explored in such fanfiction. Accelerator has a complex past and personality, and his bond with Last Order can be a source of healing for him. Fanfiction writers can show how he gradually opens up more because of her presence, and how Last Order, in turn, grows to understand him better on a deeper level.
One approach could be to introduce a third party that tries to come between them. This could be a character who is jealous of their relationship or has some ulterior motives. As Accelerator and Last Order face this external threat together, they will become more aware of their feelings for each other. Additionally, having them share personal secrets or dreams can strengthen their relationship. For example, if Last Order tells Accelerator about her hopes for the future of Academy City, and Accelerator reveals his own insecurities and how he wants to change for the better. This mutual sharing will make their connection more profound.
You can try looking on fanfiction websites such as Archive of Our Own (AO3) or FanFiction.net. These platforms usually have a wide range of fanfics, including ones related to Accelerator and Last Order. Just use their search functions to look for specific titles or keywords.
One idea could be a story where Accelerator has to protect Last Order from a new and powerful enemy. Maybe this enemy is after Last Order because of her unique abilities and Accelerator has to use all his power and strategic thinking to keep her safe.
The character development in these fanfics can be really appealing. We can see how Accelerator, who is already a complex character, grows and changes in relation to Last Order. And Last Order herself can also have her character expanded upon. Writers can delve into their emotions, thoughts, and how they interact with each other on a more personal level, which makes the fanfics interesting to read.
I'm not sure which specific 'last order x accelerator' fanfic to recommend offhand. You could try searching on fanfic websites like Archive of Our Own. They usually have a wide variety of fanfictions for different pairings.
One common theme is protection. Accelerator is often portrayed as protecting Last Order from various threats in the fanfiction, given his powerful abilities and his connection to her.