Common themes include friendship turning into love. Maybe they start as friends who support each other in their daily lives or adventures, and gradually those feelings turn romantic. Growth is also a big theme. As they fall in love, both Shinra and Maki might grow in their magical abilities or personal development. And of course, the theme of loyalty, where they stay true to each other no matter what difficulties come their way in the fanfiction world.
One possible story could be that Shinra and Maki meet in a bustling city. Shinra, with his kind heart, helps Maki when she's in a bit of trouble. They start spending more time together, going to cafes and parks. As time passes, they realize they have deep feelings for each other. They share their first kiss under a cherry blossom tree, and from then on, their love story unfolds with many sweet moments.
One common theme is sacrifice. Shinra is willing to put himself in harm's way for Maki, which shows his selfless nature. Another theme could be the growth of their relationship. After such an event, they might become closer and understand each other better. Also, heroism is a theme. Shinra is acting like a hero by protecting Maki, and this can be explored further in terms of how Maki views him as a hero and how it affects his own self - image.
Another plot could involve Tamaki getting injured during a fight. Shinra then takes it upon himself to take care of her. As he nurses her back to health, they have a lot of time to talk and get to know each other on a more personal level. This could lead to them realizing that they have a lot more in common than they initially thought, and their relationship could grow from there.
In a fanfic, their relationship could also develop through moments of vulnerability. Let's say Shinra has a nightmare about his past and Tamaki is there to comfort him. Or Tamaki has a moment of self - doubt about her abilities, and Shinra gives her an encouraging speech. These moments of showing their true selves and being there for each other can deepen their connection. It's about creating situations where they can be honest with each other and build an emotional bond.
One possible plot could be that Shinra and Maki are in a dangerous situation, like in a battle against a powerful foe. Shinra steps in front of Maki to shield her from an attack, getting hurt in the process. Maki then has to find a way to either heal Shinra or get them both to safety while still fending off the enemy. It could also involve some emotional moments where Maki realizes how much Shinra is willing to sacrifice for her.