For the Naruto side, Rock Lee would be really cool. His taijutsu - only fighting style could be really different from what the Halo characters are used to. In Halo, the Arbiter could be an interesting character to include. His story of redemption and his unique combat skills could lead to some great storylines. And of course, Hinata could also be included. Her shy but strong - willed nature could be a nice addition. She might befriend some of the Halo characters and learn new ways to fight from them.
The Master Chief is an obvious choice. His stoic and powerful presence would be really interesting in the Skyrim setting. He could be like an otherworldly hero, and his Spartan abilities would make him a force to be reckoned with against Skyrim's foes.
The Prophet of Truth from Halo could also be an interesting addition. His devious plans and manipulative ways could create a lot of chaos in the Fallout universe as he tries to gain power over the different factions and their resources.
Definitely Naruto himself. His energetic and determined personality would be a great contrast to the often more somber characters in Skyrim. Also, characters like Sasuke could be interesting. His brooding nature and powerful Sharingan abilities would make for some great interactions in Skyrim's dangerous world. And from Skyrim, the Dragonborn would be a must - include. The clash or cooperation between the Dragonborn's Thu'um and Naruto's jutsu would be really exciting to write about.
Definitely Master Chief from Halo. His skills and leadership would be a great addition to the Starship Troopers' universe. Also, Rico from Starship Troopers. He could learn a lot from Master Chief. Their interaction would be really interesting to see.
Seto Kaiba and Gary Oak would make for a fascinating pair in a crossover fanfic. Kaiba's arrogance and Gary's self - assuredness could lead to some intense rivalries. They might compete to see who can be the best in both the Yugioh and Pokemon worlds. Another interesting character would be Serena. Her kind - hearted nature could be a contrast to some of the more intense Yugioh characters. She could form bonds with the Duel Monsters in a different way than the other characters, perhaps using her compassion to calm down some of the more aggressive ones.
Definitely Percy Jackson himself. His ability to control water and his overall demigod powers would make for some really cool interactions in the Halo universe. He could be a bit of an outlier among the Spartans, but his courage and quick thinking would be assets. Also, Master Chief. His stoic and badass nature would contrast well with Percy's more impulsive and humorous side. When they team up, it would be an amazing duo to write about.
Sasuke is a great character to include. His cool and brooding personality can create interesting dynamics in crossovers. For example, if he crosses over into the world of Attack on Titan, his skills as a ninja would be put to the test against the Titans. Another interesting character is Kakashi. His laid - back yet highly skilled nature can add humor and action to crossovers. He could be a great addition in a crossover with the world of Inuyasha, sharing his knowledge of combat and jutsu.
I think Naruto and Kakashi would be very interesting characters to include. Naruto's raw power and ability to make friends easily could help bridge the gap between the two universes. Kakashi, with his Sharingan and vast combat experience, could analyze the fighting styles of the For Honor characters quickly. On the For Honor side, the Orochi would be fascinating. His quick and acrobatic fighting style could be compared and contrasted with the ninja's. And the Valkyrie, with her spear - based combat and female empowerment, could have some great interactions with the female ninja characters in Naruto.
Sasuke and the Arbiter could also be great characters to focus on. Sasuke has his own dark and brooding nature, and his powerful Sharingan abilities. The Arbiter has his own complex backstory and combat skills in the Halo universe. The contrast between their personalities and their abilities could lead to some really engaging storylines. Maybe they start off as enemies but then realize they have a common enemy in a new threat that emerges from the crossover of the two worlds.
The Arbiter and Thor. Thor is a powerful Asgardian with his hammer and lightning powers, while the Arbiter is a skilled warrior from the Halo universe. They could fight side by side against a common enemy. Their different cultures and fighting styles would make for an exciting combination. Maybe Thor could teach the Arbiter about magic, and the Arbiter could show Thor some unique Covenant combat techniques.