One possible plot could be that Clary and Jace face a lot of social stigma. Their friends might be shocked and some might even turn their backs on them. They would have to deal with their families' reactions, which could range from disappointment to support. They'd also have to figure out how to continue their education while preparing for a baby.
Well, one possible plot could be that they face challenges in their relationship due to the pregnancy. Maybe they have to deal with the reactions of their friends and family in the Shadowhunter world. They might worry about how to protect their unborn child from the various threats that exist in their world.
It would change in many ways. They would go from being carefree high school sweethearts to having a lot of responsibilities. There would be more arguments as the stress of the situation builds up. But at the same time, they would also have deeper moments of love and understanding as they face this huge life change together. Jace might become more overprotective of Clary, and Clary would need Jace's support both emotionally and physically.
Well, the plot could involve Jace and Clary dealing with the challenges of impending parenthood. Maybe they have to face the reactions of their friends and family. There could also be some sort of danger or conflict related to Clary's pregnancy, like an enemy trying to target her or the unborn child.
In this fanfic, the pregnancy could be a sign of hope for the Shadowhunter community. Clary and Jace, being two important figures, are now having a child. Their journey could involve seeking ancient knowledge from the Silent Brothers or the Iron Sisters about how to ensure the health of the baby, considering their unique genetic makeup as Shadowhunters. Along the way, they could strengthen their relationship even more as they face the challenges together.
One common theme could be the challenges they face in high school while dealing with the pregnancy. Another might be the reactions of their friends and family. For example, their friends could be either very supportive or judgmental.
Alec might also play an important role as a supporting character. He could be the voice of reason for Jace, making sure he doesn't make any hasty decisions. And Luke would surely be involved. As someone who has always been like a father figure to Clary, he would offer his wisdom and support, and maybe even help them figure out the financial aspects of having a baby so young.
Their first interaction could be intense. Maybe Jace, with his confident and somewhat brooding charm, catches Clary's eye in the hallway. She might be intrigued by his cool exterior. He could give her a lingering look, and she might blush. Then, he might say something cryptic like 'You seem different from the others here.'
Perhaps the fanfiction could focus on how their relationship evolves during the pregnancy. They might have more tender moments, but also arguments as the stress of the situation builds. For example, Jace could be overly protective, which Clary might find stifling at times. And they could also be preparing for the baby in a world full of demons and danger, like creating a magically protected nursery or finding special weapons to protect the baby when it arrives.
Jace will probably face a lot of guilt. His cheating not only hurt Clary but also has implications for the unborn child. He might find himself ostracized by their friends who side with Clary. Also, his reputation within their community in the fanfiction world could be severely damaged. If he realizes his mistake and wants to make amends, he'll have a long and difficult road ahead to earn Clary's forgiveness and trust again.
I'm not entirely sure if there is a specific 'Jace Superstar Clary Pregnant Fanfiction'. However, considering how creative fans can be, it wouldn't be a surprise. Some fans like to explore different life situations for their favorite characters. You could also check out Tumblr, as sometimes people share links to interesting fanfictions there.