A plot twist could also be that there are multiple pregnancies involved. Maybe not just Lucy is pregnant, but some other female characters in their group are also expecting at the same time due to some strange magical event. This would change the whole dynamic of their group, with everyone having to support each other in different ways and deal with the chaos that multiple pregnancies can bring.
Perhaps a plot twist could be that Lucy discovers she's pregnant but Natsu has lost his memory. He doesn't remember their relationship and is confused by the news. This would create a lot of emotional turmoil for Lucy as she tries to make Natsu remember while also dealing with the physical and mental changes of pregnancy.
One possible plot twist could be that Natsu initially doesn't believe it's his child. Maybe he has some self - doubts due to his past or his own insecurities. Another twist could be that there are external forces trying to harm Lucy because of her pregnancy, like dark guilds seeing it as a way to get to Natsu. And perhaps the pregnancy could also bring out a new side of Natsu, a more protective and responsible side that no one has seen before.
Well, a plot twist might be that they got secretly married because they made a drunken bet. One night, after a wild celebration at the guild, they made a bet that if Natsu could complete a really difficult mission on his own within a week, Lucy would marry him. Natsu, being overconfident, accepted. He completed the mission, and Lucy, being a person of her word, went through with the marriage in secret, not knowing how to break the news to their friends and guild mates.
Well, one possible plot could be that Natsu and Lucy's relationship evolves from friendship to something more romantic. Then, an unexpected pregnancy occurs which throws their lives into chaos. They might have to face the reactions of their friends and deal with their own fears and insecurities about becoming parents.
One possible plot twist could be that the pregnancy is a result of some magical interference. Maybe a spell gone wrong was meant for someone else but affected them instead. This could lead to a whole adventure of trying to find a way to reverse it or deal with the unexpected situation.
One plot idea could be that a magic spell goes wrong and Lucy ends up pregnant. Natsu is initially shocked but then quickly embraces the idea of being a father. They then have to deal with the guild's reactions, some of which are positive and some negative.
One possible plot twist could be that the father of the baby is not who everyone initially thinks. Maybe there's a secret admirer or an old acquaintance who turns out to be the father. Another plot twist could be related to the safety of the pregnancy. For example, there could be a new threat in the world she lives in that specifically targets pregnant women. Or perhaps, Michonne discovers some special powers or abilities that are awakened during her pregnancy, which is completely unexpected and changes the course of the story.
One possible plot twist could be that they face a powerful enemy who has the ability to make them forget their feelings for each other. As they struggle to regain their memories and connection, they discover new things about themselves and their relationship. Another twist could be that there is a misunderstanding caused by a jealous third party, which leads them to briefly separate before realizing the truth and coming back together stronger. And a third plot twist might be that they are forced to choose between their relationship and a great power or responsibility that could change the fate of their world.
One idea could be that they face challenges in protecting their unborn child from dark forces in the Fairy Tail world. Maybe some old enemies resurface, seeing the baby as a threat or a powerful asset. Another could be the reactions of their friends in the guild. Some might be overly excited and constantly fussing over them, while others could be more reserved and worried about the future of the guild with Natsu and Lucy having a family.
Well, one possible plot could be that Lucy has to face the challenges of pregnancy alone after Natsu leaves. She might struggle with financial difficulties and the emotional turmoil of raising a child without the father. She could then find support in her friends in the guild, who help her through the tough times and she eventually becomes a strong, independent mother.
Another plot twist could be that the father of the baby is not who they initially thought. This would create a huge amount of drama and relationship turmoil. It could also lead to a search for the real father and a battle against whoever was trying to deceive them about the pregnancy.