It could be a rival cowboy named Orochimaru. He's jealous of Sasuke's skills and the fact that Sakura is with him. Orochimaru might try to steal Sasuke's horse or sabotage their quests for supplies. He could also spread false rumors about them in the small Western towns they pass through, causing trouble for them.
Maybe a group of outlaws led by Kabuto. They see Sasuke and Sakura as easy targets. They try to rob them of their valuables, which include a special lemon - scented medicine that Sakura has made. This medicine is important for a sick child in a nearby town. So, Sasuke and Sakura have to fight off these outlaws to protect the medicine and continue their journey.
The main antagonist could be a land - greedy rancher named Danzo. He wants to take over all the land in the area, including the land where the lemon trees grow that Sakura loves. He tries to drive Sasuke and Sakura out of the region by any means necessary, setting up traps for them and hiring thugs to attack them.
Well, it could be a story where Sasuke and Sakura are in a Western - style setting. Sasuke might be a lone cowboy and Sakura a healer in the town. They meet when Sasuke gets injured and Sakura nurses him back to health. Their relationship then develops as they face challenges together in the wild West, like fighting off bandits. And the 'lemon' part could be a symbol of a fresh start or new hope in their relationship, like they find a lemon tree in the middle of the desert which gives them the strength to keep going.
It could be Orochimaru. He has always been interested in Sasuke and might kidnap Sakura to use her as bait to get Sasuke back under his control. He could be after Sasuke's power and think that by using Sakura, he can manipulate Sasuke easily.
Perhaps a new, powerful and mysterious ninja who has a vendetta against the Hidden Leaf Village where Sakura is from. He sees Zetsu as an accomplice of the village and targets both of them, causing chaos and danger in their lives. This new character could bring in a fresh and unexpected element of danger to the fanfic.
In this fanfiction, the main antagonist could be a strict teacher. Sakura, being a boy with a free - spirited nature, often clashes with the teacher's rigid rules. The teacher always seems to be out to get Sakura, giving him unfair punishments and trying to suppress his creativity or individuality.
The main characters are Sasuke and Sakura. They are well - known characters from the Naruto series. In this fanfiction, they are likely to be the central focus of the story, whether it's about their relationship or their adventures involving demons.
It could be an old enemy who has resurfaced, like Orochimaru again. Since Naruto and Sasuke are together now, Orochimaru might see them as a threat to his own plans for power and immortality.
It could be a rogue ninja who has a vendetta against Sasuke. This ninja knows that Naruto's bond with Sasuke is strong, so he uses a special jutsu to make Naruto forget Sasuke, hoping to break Sasuke's spirit. By removing Naruto from Sasuke's life in this way, the rogue ninja believes he can defeat Sasuke more easily.
Perhaps an old enemy of Sasuke's family, someone who holds a grudge against the Uchiha clan. They might see the new baby as a continuation of the Uchiha line and try to end it. This would put Sakura and Sasuke in a difficult situation where they have to use all their skills and the help of their friends to protect their baby.
It could be a powerful dark wizard who wants to use Sakura's powers for his own evil purposes. He might be constantly trying to capture her or manipulate her into doing his bidding.
Another potential antagonist could be an enemy that Orochimaru and Sakura face together during her training. This enemy might have a vendetta against Orochimaru and see Sakura as an extension of him. So while Orochimaru is training Sakura, this new enemy could be the one causing the most immediate problems and danger for them both.