I think Erza could be a top contender. Her vast array of armors and combat skills make her a force to be reckoned with. In comparison, Esdeath from Akame ga Kill is also very powerful with her ice powers. But Erza has more versatility. She could switch armors according to the situation, whether it's for defense or offense. So in a fight, she might have an advantage.
It's hard to say for sure. Natsu from Fairy Tail is extremely powerful with his dragon slayer magic. But Akame with her Murasame is also a formidable opponent. If it comes down to it, Natsu's ability to keep getting stronger in the heat of battle might give him an edge. However, Akame's stealth and the deadly nature of her weapon could also turn the tables.
Gray from Fairy Tail is a strong ice - mage. Against Akame ga Kill characters, his powers could be quite effective. However, Akame's comrades like Leone also have their own unique abilities. Leone's regenerative powers could make her a tough opponent for Gray. In the end, it really depends on the circumstances of the fight, like the location and whether there are any allies involved.
Akame would also be a top candidate. She is a stoic and deadly assassin. In a crossover, she would likely approach Devilman with caution at first. Her no - nonsense attitude and her powerful Murasame sword would make her a force to be reckoned with. It would be interesting to see how she adapts to Devilman's world and the devils she encounters, and how she might try to use her skills to take on some of the more powerful devils.
Maybe a plot where the magic in Fairy Tail is combined with the Imperial Arms in Akame ga Kill. Like, Natsu's fire magic could be used to enhance the power of an Imperial Arm. The Fairy Tail guild could also be in a conflict with the Empire from Akame ga Kill. This would lead to interesting battles and alliances between characters from both series.
Akame herself is often a very popular character in these crossovers. Her deadly skills and cool demeanor make her an interesting addition to any crossover scenario. Tatsumi is also popular as he is one of the main characters in Akame ga Kill and his journey of growth and development can be further explored in crossovers. Esdeath is another one. Her powerful and somewhat sadistic nature can create a lot of tension and interesting plot twists when combined with characters from other anime in crossovers.
Sasuke and Esdeath could be a fascinating pairing. Both are extremely powerful and have a certain ruthlessness. However, Sasuke has his own moral code which would clash with Esdeath's more extreme views. This conflict could drive an intense story.
Well, likely the main character from the original 'Akame ga Kill' will still play a significant role. Akame herself might be one of the main characters as she has to deal with the new situation involving the Reincarnation Emperor.
A well - developed character is key. The powerful OC should have a backstory that makes sense within the Akame ga Kill universe. For example, if they're a powerful fighter, there should be an explanation for how they got those skills, like being trained in a secret martial arts sect or having a special weapon inheritance.
Hashirama would likely be very confused at first in the world of Akame ga Kill. But being a natural leader, he would soon start to understand the power dynamics. He might interact with Akame by respecting her skills as a fighter and offer his own knowledge of combat and strategy. Akame, in turn, would be intrigued by Hashirama's strange powers.
The main characters include Tatsumi, a naive yet brave young man. Akame, a skilled assassin with a cold exterior. Leone, who has the ability to transform into a half - beast. There's also Mine, a sniper with a sharp tongue. And Bulat, a strong and noble warrior who mentors Tatsumi.
Quite a few characters die. Some major ones include Chelsea and Susanoo. But it's best to read it to get the full impact.
But we also can't forget about Ichigo in his final form. He has the power of a Soul King and his combat skills are top - notch. If he were to enter the Fairy Tail world with all his power, he would be able to take on most threats with ease. It really depends on how the crossover is written and what kind of challenges are presented to each character.