She could be from a hidden clan. Maybe her clan was in charge of protecting a powerful and ancient artifact. But when the Nighloks started getting more aggressive, her clan decided it was time for her to join the Power Rangers. Her skills with the katana, which she learned from her clan's strict training regime, would be a great asset to the team.
Conner, another member of the Dino Thunder team, is a great character to pair with the Green Ranger. They could have a friendly rivalry that turns into a strong friendship as they face challenges together. Their different personalities, with Conner being more impulsive and the Green Ranger perhaps more reserved, would create an interesting dynamic.
One interesting storyline could be the Green Ranger OC coming from a different dimension where the rules of power are different. They have to adjust to the new team while also bringing in their unique combat skills. For example, they might have a special way of summoning their zord that the other Rangers have never seen before.
Consider their backstory. They could be an outcast from their own planet who was found and trained by an old, retired Power Ranger. Their alien origin gives them a different perspective on things. Also, their suit design can be unique. Instead of the regular green, it could have some blue accents or different symbols that represent their individuality.
The Pink Ranger could be an interesting character to pair with the Black Ranger. Maybe they have a love - interest kind of relationship where their different personalities clash at first but then they grow to understand and care for each other. Also, a villain who has a personal vendetta against the Black Ranger could be paired with him in a story. This would create a lot of tension and conflict, making for an exciting plot.
A great plot might involve the Black Ranger getting lost in a different dimension while on a mission. In this dimension, he has to adapt to new rules and powers while trying to find his way back. He could meet new allies or face enemies that are unique to that place. Also, a plot about the Black Ranger having to train a new recruit who has a lot of potential but also a lot of recklessness could be interesting.
Her powers could be more focused on stealth. While the other rangers are great at direct combat, she can move silently and strike without being noticed. For example, she might be able to turn invisible for short periods, which would give her an edge in surprise attacks.
Another storyline could involve the Green Ranger's past. Perhaps he has a family member who was also involved with the Rangers in some way long ago. This family connection could come back to haunt him or help him, like if there was an old enemy that recognizes his family name and targets him specifically. He then has to figure out how to deal with this new threat while also keeping his team informed and safe.
One possible love story could be that Jayden meets a new ranger from another team during a joint mission. They start off as comrades but gradually realize their feelings for each other as they face various challenges together. Their love blossoms as they support one another through tough battles against powerful enemies.
Another idea is a character swap. Picture Naruto as a Power Ranger Samurai. He would bring his ninja skills and determination to the team. His Rasengan could be transformed into a special attack for his Samurai Zord. Or, a Power Ranger Samurai could be sent to the Naruto world and have to learn ninja techniques to survive and help the village.