What could be the possible motives in a manny ruiz kidnaps sam gh fanfiction?

I'm not sure specifically if there is a fanfiction with that exact plot. You could try searching on major fanfiction websites like Archive of Our Own or FanFiction.net.

It could be that Naruto has lost his sanity temporarily. The stress of being a hero, the constant battles, and the losses he has endured might have taken a toll on his mental state. In this state of instability, he may see Sakura as a symbol of something he wants to preserve or protect, but his way of doing so is through kidnapping. Or there could be a new villain in the story who has the ability to make Naruto act out of character, and this villain's plan involves Naruto kidnapping Sakura.

Well, it could be out of jealousy. Maybe Dean feels like he's losing Ginny to someone else and in a moment of madness, decides to kidnap her. But this is all just speculation within the wild world of fanfiction.

It could also be for power. Perhaps Stiles has some knowledge or ability that Theo wants to use for his own gain. In the show, Stiles was quite smart and resourceful, so Theo might kidnap him to get access to that intelligence or those skills. In some fanfictions, Theo might be trying to use Stiles as a bargaining chip to get something from the other characters like Scott or Derek.

Well, in this kind of fanfiction, Doc Oc could kidnap Spiderman to force him to reveal his identity. Doc Oc might think that knowing who Spiderman really is would give him an upper hand in their ongoing battles. It could also be that Doc Oc wants to study Spiderman's powers. He's a scientist after all, and Spiderman's abilities are quite unique. He might believe that by kidnapping and examining Spiderman, he can find a way to replicate or counter those powers.

Perhaps Fleur is being controlled or influenced by a dark force. In the Harry Potter universe, there are many dark magic entities that could manipulate someone into kidnapping Harry. It could be that she is under the Imperius Curse or some other form of mind control. Another reason could be that she has some sort of personal vendetta against Harry or those close to him, and kidnapping him is her way of getting revenge. She might think that Harry has wronged her in some way, whether it's real or just in her deluded perception.

Maybe she's trying to protect Naruto from something she knows about but others don't. She might think that by kidnapping him, she can keep him safe from an imminent threat that the village or his friends are unaware of.

One possible motive could be revenge. Maybe Nightwing has thwarted Slade's plans in the past, and Slade wants to get back at him. Another could be that Slade sees Nightwing as a valuable asset. He might plan to use Nightwing's skills for his own evil purposes, like forcing him to steal something or gather information for him.

Well, his motive might be related to his twisted sense of love. In the context of fanfiction, Hannibal could think that by kidnapping Will, he is protecting him. He may view the world as a dangerous place for Will, and his actions are a way to keep Will safe in his own, very abnormal way. Also, it could be a power play. He wants to show that he has the power to take Will whenever he wants, asserting his dominance over Will.

One possible motive could be that in the fanfiction, Adrien is being controlled by some dark magic or an evil force. This external influence makes him act against his true nature and kidnap Marinette. For example, perhaps a villain has cast a spell on him to use him as a tool to get to Marinette, who might have some special power or knowledge that the villain desires.