Another plot could be that they are both outcasts in their own ways. The male Shepard has made some controversial decisions, and the female Krogan doesn't conform to the traditional Krogan female roles. They find solace and understanding in each other as they try to carve out a new place for themselves in the galaxy.
Maybe the story could start with the male Shepard saving the Turian female's life during a skirmish. She then feels indebted to him and joins his crew. During their travels, they learn about each other's cultures. The Turian female teaches Shepard about Turian traditions, and Shepard shares stories of Earth, which brings them closer.
Perhaps they meet on a new planet that has some strange energy. This energy affects their emotions and they start to see each other in a different light. They have to figure out how to control this new situation while also dealing with their growing feelings.
One plot idea could be Shepard and Liara dealing with the challenges of impending parenthood while also facing the threats in the Mass Effect universe. For example, they might have to protect their unborn child from the Reapers or other dangerous forces.
Another plot could revolve around the baby's growth and discovery of its identity. Growing up in a universe full of different species and cultures, the baby might struggle with where it belongs. It could go on a journey of self - discovery, with Shepard and Liara guiding it, and along the way, they all learn more about each other and the wider Mass Effect universe.
The theme of strength also stands out. Being raised by Krogan, she's often portrayed as having a physical and mental strength that surprises others. There's also the theme of redemption in some cases. For example, if there have been past conflicts between Krogan and humans, she might play a role in redeeming the Krogan in the eyes of humans or vice versa.
In fanfiction, their relationship might develop through a series of adventures. For example, they are on a quest to find a powerful artifact. Along the way, they face many difficulties and have to rely on each other. The male Shepard might learn to trust the female Krogan completely, and she might see him as someone different from the other humans she has encountered. This trust and mutual dependence can lead to a strong relationship.
An interesting plot could be that her pregnancy is a result of some alien experiment gone wrong, and she has to find a way to reverse it while also dealing with the fact that she's starting to feel a strange connection to the unborn child. This could lead her on a journey to find a cure and also discover the true intentions behind the experiment.
A really interesting plot could be that there's a threat that endangers both the Harry Potter universe and Fem Shepard's universe. So, a group of characters from both worlds, led by Harry and Fem Shepard, come together. They have to combine magic and technology to defeat this threat. Fem Shepard could introduce the wizards to advanced weaponry from her world, while the wizards teach her and her crew about magic spells and potions.
One great fanfic could be 'Krogan's Daughter: The Shepard Story'. It really delves into how her upbringing by the Krogan shapes her character. She has a tough - as - nails attitude and a unique perspective on galactic politics due to her Krogan - influenced upbringing.
One plot idea could be that Female Shepard and Vega are on a dangerous mission together. They get separated from the rest of the team in a hostile alien environment. As they struggle to find their way back, they have to rely on each other's skills. Vega's combat expertise and Shepard's strategic mind work in tandem to fend off various threats. Along the way, they start to understand each other on a deeper level and form a strong bond.