One idea could be exploring T'Challa's relationship with an original character (OC) during his time as king. The OC could be a diplomat from another nation, and their interactions could involve political intrigue and cultural exchanges.
Another interesting angle is an OC who is a warrior from a rival tribe. T'Challa has to deal with this OC's presence in Wakanda and they gradually learn to respect each other and work towards a common goal.
Perhaps a story where an OC is a scientist who helps T'Challa develop new technology for Wakanda. This could include details about the scientific process and how they overcome challenges together.
One idea could be that deaged Tony and T'Challa have to work together to solve a mystery in their shrunken state. Maybe they use their unique skills but in a more child - like and innocent way.
Perhaps a plot where T'Challa has to go undercover in different parts of the world and ends up relying on the help of many different individuals. This would create a lot of interesting character dynamics as he builds relationships with people he might not have otherwise interacted with.
One common theme is the clash of cultures. Since T'Challa is from Wakanda, an advanced and unique African nation, and the oc often comes from a different background, there's a lot of exploration of how their different cultures interact. Another theme is the power of destiny. In these stories, it's often fated that they are soulmates and they have to overcome various obstacles to be together.
One interesting plot could be them teaming up to solve a global energy crisis. Tony's technological expertise and T'Challa's knowledge of Wakandan resources combine to create a new, sustainable energy source. Another plot might involve them facing a common enemy who is stealing advanced technology from both Stark Industries and Wakanda. They have to use their wits and unique abilities to stop the thief.
One interesting fanfiction could be about T'Challa's adventures in a parallel universe. In this story, he teams up with other superheroes from different realms to fight a powerful, universe - threatening villain. It could explore how his Wakandan technology and his skills as the Black Panther blend with the powers of his new allies.
One great t'challa oc soulmate fanfiction is 'Soulbound to the King' which beautifully weaves a story of an original character finding their soulmate in T'Challa. The story has a lot of emotional depth and the relationship development is very engaging.
One great t'challa fanfiction could be about his adventures outside of Wakanda, exploring new lands and cultures. It might involve him making new allies and facing unique challenges.
Maybe the reader is an inventor who creates a technology that could potentially end the conflict in Civil War. T'Challa is intrigued by this and wants to work with the reader. Along the way, a relationship develops. For example, they might face challenges from other factions who don't want the conflict to end so easily and try to stop their collaboration, which in turn brings them closer.
Shuri would be an obvious choice. Their sibling relationship could be explored in different ways, like her helping him with scientific projects while he teaches her about leadership. Also, Nakia could be a great pairing. Their love story could be delved deeper into, with adventures that test their relationship.
One possible plot could be a story where the main character, a regular citizen, accidentally bumps into T'Challa and in that moment, a spark of attraction leads to a spontaneous kiss. It then delves into how their relationship develops in the face of his responsibilities as the Black Panther.