Penny could be an unexpected ally. She's an android, which is a very different kind of being compared to Dead Pool. Her naivete and eagerness to help, along with her unique abilities like being able to split into multiple parts, could pair up strangely but effectively with Dead Pool. Dead Pool might find her both fascinating and useful, and together they could cause all sorts of chaos and also some good in the RWBY world.
Ruby could be an unexpected ally. Given her innocent and positive nature, teaming up with the wild and unpredictable Dead Pool would be quite a contrast. But her leadership skills and powerful scythe - wielding abilities could complement Dead Pool's combat style in unexpected ways.
A monster that Percy has previously fought. For example, a Minotaur. It could have been given a second chance at life by a god and now owes a debt to Percy. It might seem strange at first, but its brute strength and knowledge of the Underworld could prove useful in protecting the gods.
An unexpected ally could be an old enemy from his past. Maybe a Hollow that he once fought and defeated now sees a greater threat in the situation after Ichigo's revival and decides to team up with him. For example, the Hollow might have information about the new forces that are emerging since Ichigo's return and offers to share that in exchange for some form of protection or mutual benefit.
One interesting concept could be the combination of Dead Pool's chaotic and irreverent personality with the unique world and characters of RWBY. For example, Dead Pool might make jokes and break the fourth wall in the RWBY universe, which could add a whole new level of humor. His combat style, which is unorthodox and violent, could also create some really cool fight scenes when paired with RWBY's action - packed battles.
A little mouse in the maze could be her unexpected ally. It might know all the secret passages and hidden corners of the maze and could lead her to safety or important clues.
Maybe Dobby could be an unexpected ally. He could use his magic to create distractions for the other contestants or help Harry find a hidden passage in the maze. Another possibility is that one of the Hogwarts ghosts, like Nearly Headless Nick, decides to assist Harry. He could float through walls and spy on the other champions' movements and relay the information to Harry.
The unexpected ally might be a character from a different village, like Gaara from the Sand Village. Gaara has a deep respect for Naruto and has changed his ways after his encounter with Naruto. In this fanfiction, Gaara could come to the aid of the Hidden Leaf Village because he believes that the safety of all villages is interconnected. His unique sand - based powers would add a different dimension to the fight to save the Hidden Leaf Village.
Darth Vader could be an unexpected ally in a time travel scenario. If Luke travels to a time when Vader was still Anakin Skywalker and on the verge of turning to the dark side, Luke could try to prevent his fall. In the process, Anakin might become an ally, using his skills as a powerful Jedi to help Luke in whatever mission he has in that time period.
His unexpected ally could be a minor god from the past. Maybe a god that was forgotten in his own time but still has some power in the past time period Percy travels to. This god could help Percy because they see an opportunity to regain some status through Percy's actions in the present time. Another possibility is an enemy from his own time who has different motives in the past and ends up working with Percy.
Boruto could be an unexpected ally. Maybe he somehow gets caught up in the time - travel event with Sarada. They have a strong bond in their own time, and that would carry over. They could work together to face the challenges of the different time periods, like when they encounter powerful and dangerous ninjas from the past or future.
Poison Ivy could be her ally during time travel. Since they have a strong bond in their own time, Ivy could follow Harley through time accidentally. And Ivy's connection to nature might be useful in different time periods. For instance, in a pre - industrial Gotham, Ivy could use her powers to communicate with the natural world to find a way to get them back to their own time.