The baby might have Bella's big, expressive eyes and Damon's dark, tousled hair. Maybe it would inherit Bella's pale complexion and Damon's sharp facial features. Since they both have a certain allure in their respective shows, the baby could be extremely beautiful or handsome, with an otherworldly charm.
In the fanfiction, perhaps the baby's birth is a very difficult and dangerous process. Since both Bella and Damon are from different fictional universes with their own set of rules regarding vampires and such. The baby could be a symbol of a new beginning for their relationship, forcing them to put aside their differences and work together to protect their child. They may have to face challenges from both the vampire and human communities who are either afraid of or envious of the baby.
Their baby could look very much like a normal human baby at first glance, but on closer inspection, it has some mermaid - like qualities. For example, its ears might be slightly pointed like Ariel's, and when it's in the water, it seems to move with an unusual grace. It has a beautiful face with a combination of Ariel and Eric's best features, and its skin has a soft, almost iridescent sheen in certain lights.
Well, it could have a body shape that's a mix of Greninja's sleek and athletic build and Delphox's more elegant and slender form. Its head might be more like Greninja's with a sort of frog - like appearance, but with Delphox's fiery markings around its eyes. It may also have a tail that combines the features of Greninja's small tail and Delphox's large, bushy tail, perhaps with some sort of water - fire elemental design on it.
Bella might be very empathetic. Since she's in a family full of complex emotions, she can sense when Damon is feeling particularly broody or when Stefan is stressed. So she tries to comfort them in her own way, like making them a special meal or just sitting and listening to their problems.
In fanfiction, the baby could inherit Sesshomaru's grace and strength. It could have a lithe body like him. However, it would also have Kagome's human charm. Its eyes could be a mixture of Sesshomaru's intense gold and Kagome's brown, creating a really unique and alluring look. And perhaps it would have some sort of special power that combines Sesshomaru's demon abilities, such as his speed and regeneration, with Kagome's spiritual powers.
Bella would be extremely loving and nurturing. She would spend a great deal of time just holding the baby, looking into its eyes, and talking softly to it. Jasper, on the other hand, would be very protective. He would use his ability to sense and manipulate emotions to keep the baby calm and happy.
She could have Katniss's dark hair and Peeta's blue eyes. Her features might be a blend of their strong and determined looks. Maybe she has Katniss's high cheekbones and Peeta's soft - looking lips.
The baby could be a really interesting mix. It might have Hermione's bushy hair and Legolas' pointed ears. And perhaps inherit Hermione's intelligence and love for books as well as Legolas' amazing archery skills and connection to nature.
Damon would likely become more protective and responsible. He might start to see the value in a more stable life. Elena would grow in her maternal instincts and become even more of a force to be reckoned with when it comes to protecting her family.
Well, at first, they might be a bit clumsy in their new roles as parents. Damon, who is used to being a bit of a loner, would have to open up more to Bonnie and the baby. Bonnie would be more in control in some ways, as she would use her witch knowledge to take care of the baby. Their relationship would shift from just being a couple in love to a family unit, with all the added responsibilities and deeper emotional bonds that come with it.