Thor would be very worried about Jane's safety. He would probably feel guilty too, as he might think it's his fault for getting Jane involved in his world. He would be relentless in his search, calling on his friends and allies in Asgard and on Earth to help him find her.
Thor would be furious. He would immediately start looking for Jane, using all his resources. He might first try to reason with Loki, but if that doesn't work, he would not hesitate to use force.
At first, Bruce might be scared. He knows Loki's reputation for being unpredictable and dangerous. But he also tries to keep his cool because he doesn't want to accidentally transform into the Hulk right away. He might try to reason with Loki, using his intelligence to talk his way out of the situation.
She might try to manipulate Loki. Natasha is very good at getting into people's heads. She could play on Loki's ego or his own insecurities to gain an advantage. For example, she could pretend to be interested in his plans or offer to help him in some way, all while secretly planning her escape.
In some cases, the reader could be in a state of shock and disbelief. They might not believe that this is really happening. But as they come to terms with the situation, they could start to form a plan. Maybe they try to appeal to Loki's better nature, if they believe he has one, by talking about his past actions and relationships that show his capacity for good.
Captain America would probably remain calm at first. He's used to being in tough situations. He'd try to talk to Loki, reason with him, and find out what Loki wants.
Thor could also become very angry. Not at Loki, but at whatever or whoever caused those scars. He might vow to avenge Loki and seek out those responsible. For example, if the scars were from a battle with a particular enemy, Thor would be determined to confront that foe.
One possible scenario in this fanfiction could be that Loki disguises himself and lures Spiderman into a trap. He then transports him to a different realm where Spiderman is completely out of his element. Spiderman would have to rely on his wits and basic powers to try and escape Loki's clutches.
The other Asgardians would be in shock. Heimdall, for instance, would immediately sense that something was wrong with Thor. He might try to find a way to break the spell himself or inform the other powerful Asgardians. Odin would be furious with Loki and demand that he unfreeze Thor. The Warriors Three - Fandral, Hogun, and Volstagg - would likely want to take immediate action against Loki. They might try to fight him to force him to reverse the spell.
There's 'Thor's Redemption in Loki's Arms'. In this story, Thor realizes his true feelings for Loki after a series of events that nearly tear Asgard apart. It's a tale full of emotion and character development.
If Loki kidnaps Spiderman in fanfiction, it would be a very interesting plot. Loki is a powerful and cunning character, while Spiderman is a beloved hero. Loki might underestimate Spiderman's resourcefulness though. Spiderman could use his spider - sense to find weaknesses in Loki's plans.
One possible outcome in this fanfiction could be that Loki kidnaps Darcy for a very specific reason. Maybe he needs her knowledge of some scientific concept that is relevant in the world he is from or is planning to use in his schemes. For example, if Darcy has been working on some sort of energy research that Loki believes can be harnessed for his own power - enhancing purposes.