Perhaps it could be a fanfic where they meet during a grand magical event. Plague Knight is initially distrusted due to his association with plagues, but Sona sees the good in him. They then team up to stop an evil force that is threatening to disrupt the harmony of their world. The story could explore how their different powers complement each other.
In the fanfic, their relationship could develop in stages. Initially, it could be a relationship of necessity. They need each other to achieve a certain goal, like saving a kingdom from a plague or an otherworldly threat. As they spend more time together, they start to understand each other's quirks and values. This understanding could lead to a deeper emotional bond, whether it's a strong friendship or a more romantic connection. For example, Plague Knight might learn to be more gentle and considerate from Sona, while Sona could gain a sense of adventure from Plague Knight.
One idea could be that they meet in a neutral magical realm. Plague Knight is intrigued by Sona's unique musical magic and Sona is curious about Plague Knight's alchemical skills. They start to exchange knowledge, which gradually turns into a deeper connection.
Another place to search could be FanFiction.net. It has a large collection of fanfictions. However, the quality can vary a great deal. When you search for 'Plague Knight x Sona' there, you might have to sift through some stories to find the ones that really appeal to you. Some might be more focused on action, while others could be more about the relationship development between the two characters.
One possible plotline could be that they meet in a dangerous situation, like a battle - ridden landscape. Plague Knight might be initially suspicious of Mona, but as they face challenges together, they start to develop feelings for each other.
The contrast between their characters. Thresh is a dark and menacing figure, while Sona is more of an ethereal and benevolent presence. Their interaction in a fanfic can create a really interesting dynamic.
I'm not sure of specific 'Plague Knight x Mona' fanfics off - hand. You could try searching on popular fanfic websites like Archive of Our Own. There might be some interesting stories there written by fans who are into this pairing.
One popular 'issei x sona fanfic' could be 'A Chance Encounter'. It beautifully weaves a story of how Issei and Sona meet in an unexpected situation and how their relationship develops from there. Their interactions are full of charm and the plot often has interesting twists.
A common theme is friendship. The oc might start as a friend to Sona Sitri and then the relationship could develop further. Another theme could be adventure, where they go on quests together in the High School DxD universe.
Well, one key element is the combination of Naruto's world and the Sona group's characteristics. Naruto's ninja skills and the Sona group's special traits often create interesting scenarios. For example, Naruto's ability to use shadow clones might be combined with the Sona group's magic or powers in some fanfics.