Well, Bella is a character who might be a bit naive or just unlucky to find herself in the company of drunk guys. Edward, with his centuries - old wisdom and vampire powers, is the one who swoops in to save the day. He is the protector, the one who will go to great lengths to keep Bella safe. Bella, in turn, is the one who makes Edward feel more human, and his need to protect her is part of what drives their relationship in this fanfiction.
One possible scenario could be that Bella is out alone at night and a group of drunk guys start harassing her. Edward, with his vampire speed and strength, appears out of nowhere and scares the drunk guys away. He then takes Bella to a safe place, like his house or a quiet café.
The main characters are obviously Edward and Bella. Edward is the vampire who saves Bella. Bella is the human in danger from James.
She might be in shock at first. After all, she was in a life - threatening situation. But then she could feel extremely grateful towards Edward and their relationship might grow stronger.
Bella would likely be very frightened during the car incident. Once Edward saves her, she'd be extremely relieved and probably feel even more attached to him. Edward, on the other hand, would be initially worried and focused on getting Bella to safety. After saving her, he might feel a sense of relief as well, but also a bit of that over - protective feeling that he often has for Bella.
In many such fanfictions, Edward might use his superhuman speed to reach Bella just in time. He could have sensed her danger through his vampire instincts and dashed to the cliff edge, grabbing her before she falls.
The main characters are Percy and Annabeth. Percy is the hero of the story. His role is to save Annabeth from drowning. He uses his skills, especially his ability to control water, to reach her and get her to safety. Annabeth, on the other hand, is the damsel in distress in this fanfiction. Usually, she's a strong character, but in this situation, she needs Percy's help. Her role also includes being the reason Percy shows his heroism and loyalty to her.
The main characters are Derek, Stiles, and Gerard. Derek is the savior. He's a werewolf with strength and abilities that he uses to protect Stiles. Stiles is the one in danger. He might be a human who often gets into trouble but has a good heart. Gerard is the antagonist. He likely has some malicious intentions towards Stiles, which is why Derek has to save Stiles from him.
The main characters are Naruto, Rias, and Riser. Naruto is the savior. He comes from his own world of ninjas with his extraordinary skills and powers. His role is to rescue Rias from the clutches of Riser. Rias is the damsel in distress. She's in a difficult situation where she needs someone to save her from Riser. Riser is the antagonist. He's the one causing trouble for Rias and is the obstacle that Naruto has to overcome in order to save her.
One possible reason could be that Edward believes Charlie is a threat to Bella in some way that Charlie doesn't realize himself. Maybe Charlie unknowingly gets involved with some dangerous elements, and Edward, with his vampire senses, detects it.
Edward could use his mind - reading ability. He reads Charlie's intentions and plans his moves accordingly. If Charlie is about to make a decision that Edward believes will be bad for Bella, he can intervene at the right time. He might also be able to manipulate the situation subtly so that Charlie changes his mind without realizing it.