Billy and Kelli are the key characters. In fanfiction, they can be portrayed in different ways. Maybe Billy is the more impulsive one while Kelli is the more cautious and logical. Their different personalities often drive the plot forward.
The main characters are Billy and Kelli, of course. They are likely to be at the center of whatever stories are created in the fanfiction.
One interesting story could be about Billy and Kelli's adventure in a new scientific experiment gone wrong. They might have to use their unique skills to fix things.
Well, of course, Daniel is a main character. He is often the focus as the story usually revolves around his actions and his relationship with the other bionic characters from the Lab Rats series.
Obviously, Taylor and Leo are the main characters. Taylor is often portrayed as a smart and independent character. Leo, on the other hand, is usually shown as someone who is kind - hearted and has a good relationship with the lab rats.
The main characters would obviously be the lab rats and Donald. The lab rats are likely to be the pursuers, and Donald is the one being chased.
The main characters are typically the Lab Rats - Adam, Bree, and Chase. They are bionic teens with unique abilities. And of course, Victor Krane, who is often the antagonist in the original series but can be portrayed in different lights in fanfiction. He is a brilliant but often misguided scientist. Sometimes, other characters like Mr. Davenport or Leo may also be important in the fanfiction, depending on the plot.
Most likely the two lab rats in love are the main characters. But there could also be some supporting characters like the scientists who take care of them or other lab animals.
Definitely Adam, Bree, and Chase. Adam with his super strength could be trying to break through the barriers of the speed trap. Bree, with her super speed, might be both a target of the trap (as it's speed - related) and also a key to getting out. And Chase, being the intelligent one, would be figuring out how the trap works and formulating plans to escape. There could also be Mr. Davenport involved, as he is their mentor and might be trying to help them from the outside or get trapped with them and use his technological knowledge to find a solution.
Obviously, Tasha would be a main character as she is the one who is pregnant. Donald could also be a main character as he is her husband and would be involved in the pregnancy journey. The bionic kids, like Chase, Bree, and Leo, would also be important main characters as they are part of the family and their reactions and actions would play a big role in the story.
Obviously, AJ is one of the main characters. She is often the center of the action in these fanfictions, with her unique skills and personality. Then there are the members of the Lab Rats Elite Force like Chase, Bree, and Kaz. They usually interact with AJ in different ways, sometimes as teammates and other times as friends or rivals.
Based on the title, Adam is likely one of the main characters. And of course, the lab rats are also main characters. Adam could be a scientist, a lab technician, or just someone who has a lot to do with the lab rats in this love - centered story.