A more emotional plot could be about Jem and Tessa's fear of not being good parents. They might have flashbacks to their own difficult childhoods or experiences in the shadowhunter world that make them worry. But as they bond with the baby, they gradually overcome these fears and grow into confident parents.
One idea could be focusing on how Jem and Tessa prepare for the baby's arrival. They might be seen shopping for baby clothes and nursery items, arguing gently over colors and styles.
Another plot could revolve around the baby's first supernatural encounter. Since Jem and Tessa are from a world full of magic, perhaps the baby shows an early sign of special powers, and they have to figure out how to handle it. They could consult their friends and allies in the shadowhunter world for advice.
Demons might also be antagonists. They sense the new life which has a connection to powerful shadowhunters like Jem and Tessa and see it as an opportunity to strike at the shadowhunter community. They could try to possess the baby or harm it in some way.
Tessa Jem fanfic often explores unique relationships and alternate storylines. It can offer fresh perspectives on the characters.
One interesting Tessa and Hardin baby fanfiction could be about their journey of becoming parents and how they adjust to the new life with a baby. For example, it might focus on the challenges they face like lack of sleep and the joys of seeing their baby's first smile.
One idea could be a story where they form an unlikely alliance in the wrestling world. They team up to take on a common enemy, perhaps a powerful wrestling stable that has been causing trouble for both of them. Along the way, they develop a deep respect for each other's skills.
One idea could be that baby Mario and baby Luigi get lost in a magical forest filled with strange creatures. They have to use their baby wits and little jumps to get through obstacles and find their way back home. Maybe they befriend a little fairy who guides them part of the way.
One idea could be that Baby Mario and Baby Peach go on a magical adventure through the Mushroom Kingdom, encountering new and strange creatures along the way. They might have to work together to solve puzzles to reach a special power - up that can save the kingdom from a new threat.
One idea could be a story where the baby in the 'baby project' has some sort of special power that the characters have to figure out how to manage. Maybe the baby can communicate telepathically and it leads to all sorts of comical and heartwarming situations as the characters try to understand what the baby wants.
One plot idea could be that Baby 5 and Sai are on a mission together. They start off not getting along well because of their different personalities. Baby 5 is impulsive and Sai is more reserved. But as the mission progresses, they begin to understand each other's strengths and develop a mutual respect. They end up saving each other during a dangerous encounter and form a strong friendship.
One idea could be about the baby's first adventure in a magical garden. Maybe the baby discovers a hidden path and meets talking animals who teach it about the magic of nature.
One idea could be that the baby has a special power that tames the beast. For example, the baby's laughter might have a calming effect on the usually fierce beast.