The baby can introduce a new emotional aspect. The characters in Fairy Tail are known for their strong emotions, and the presence of a helpless baby can bring out their protective and nurturing sides, changing their relationships with each other.
It could be a catalyst for a new adventure. For example, if the baby has a special mark, it might lead the guild to search for the origin of that mark. This could involve traveling to new places, facing new enemies, and uncovering secrets about the Fairy Tail world that were previously unknown. The baby is like a key that unlocks a whole new part of the story.
One possibility is that the baby could be a key to a long - forgotten prophecy in the Fairy Tail universe. Maybe it has special powers that the villains in the fanfiction are after, and the Fairy Tail guild has to protect it.
It can add new plot elements. For instance, Envy's presence might introduce new conflicts that the Fairy Tail characters have to face. This could change the direction of some story arcs in the original Fairy Tail.
One idea could be that Baby Naruto somehow gets transported to the Fairy Tail world. He could end up being taken in by one of the guild members, like Lucy. Since he's a baby, he'd be super cute and the members would be protective of him. They might even try to train him in their magic, which could lead to some really interesting and funny situations as Naruto tries to adapt to this new world of magic.
In many fanfictions, when Wendy is hurt, it unites the Fairy Tail guild. For example, they might all come together to find a cure if she's been poisoned or injured by a special magic. Her hurt makes everyone more determined to protect each other.
One possibility could be that they discover they're having a baby unexpectedly. Natsu might be initially confused but then super excited. Lucy would probably be a bit more practical, thinking about how to raise the baby in the Fairy Tail guild environment. The guild members would be overjoyed and offer all kinds of help, like Happy bringing little gifts for the baby to be.
One idea could be that Natsu and Lucy accidentally end up taking care of a baby dragon. Natsu would be excited to teach it fire - breathing tricks while Lucy would be more focused on keeping it safe and fed. Another plot could involve a magic spell gone wrong that turns them into babies themselves, and they have to figure out how to reverse it while in this state. It could also be a story where they find a lost baby in the forest during one of their quests, and they decide to raise it together, which would show their growth as characters in terms of responsibility.
The OC's reincarnation can have a huge impact. If they are reincarnated as a new member, they can bring fresh perspectives to the relationships. For example, they might befriend characters who were previously on the outskirts of the guild. If reincarnated as an existing character's relative, it can strengthen or complicate family - like relationships. They could also introduce new rivalries if they have different beliefs or goals compared to other members.
It could be about Natsu having left Fairy Tail for some reason and then reuniting with the guild in a very unexpected way. Maybe he has new powers or a different outlook on life that causes some friction and also some amazing moments of reunion and growth within the guild.
There could be a 'fairy tail baby fanfiction' where a time - traveling baby arrives in the Fairy Tail world. This baby has knowledge of future events and the characters have to figure out how to deal with this. Some might be skeptical, while others like Lucy might be more open - minded and try to understand the baby's cryptic messages.
Characters in 'Fairy Tail' fanfiction with 'not normal magic' often have to face new challenges related to that magic. They might struggle to control it at first, like if it's a very volatile form of magic. This internal struggle can be a major part of their character arc. And if the magic is something that society in the 'Fairy Tail' world doesn't understand or fears, they could face discrimination or be hunted, which further complicates their story.