Archive of Our Own (AO3) is a good place to start. It has a vast amount of fanfiction, and you can use the search function to look for Mika x Yuu mpreg specifically. Just type in the relevant tags and see what comes up.
I'm not sure specifically about Mika x Yuu mpreg fanfiction. You could try searching on some popular fanfiction websites like Archive of Our Own. They have a large collection of various fanfictions, but it may or may not have exactly what you're looking for.
A 'possessive mika x yuu fanfiction' could be centered around the idea of Mika's territorial feelings towards Yuu. This could be due to their shared past experiences. For example, they might have grown up together in a difficult situation, and Mika feels the need to protect Yuu in an almost possessive way. The fanfiction might show how Yuu reacts to this possessiveness, whether he accepts it or tries to break free from it.
Yes, Mika does call Yuu 'Yuu-chan' in the manga.
I don't really support or promote lemon fanfiction due to its often inappropriate nature. But generally, in non - appropriate fanfictions, common themes might be about their relationship dynamics in an overly sexualized way which is not suitable for public discussion.
Another theme is sacrifice. In many fanfictions, either Mika or Yuu is willing to sacrifice themselves for the other's well - being. For example, they might put themselves in danger to protect the other from harm.
Definitely. Fanfiction writers often create interesting scenarios for Mika and Yuu in the Yaoi genre. For example, they might write about how they first realize their feelings for each other. You can also check fanfiction forums where people might recommend their favorite Mika x Yuu Yaoi fanfictions.
One popular theme is the exploration of their friendship in extreme situations. How they support each other when facing powerful enemies in the Owari no Seraph universe.
One great Mika x Yuu fanfiction is 'The Bond Beyond'. It beautifully explores their relationship in a post - apocalyptic world. The story focuses on how they rely on each other for survival and how their bond deepens over time.
One common theme is loyalty. Mika's possessiveness can be seen as an extreme form of loyalty towards Yuu. Another theme is protection. Since Mika is possessive, he often tries to protect Yuu from any harm. And there's also the theme of jealousy. If other characters get too close to Yuu, Mika's possessive nature will make him jealous.
I'm not sure specifically which 'Mika x Yuu lemon fanfiction' is good. You could try searching on some popular fanfiction websites like Archive of Our Own. There might be a variety of works there that match what you're looking for.