One possible plot could be that Kratos, from God of War, somehow ends up in the Assassin's Creed universe. He teams up with an Assassin, perhaps Ezio. Together, they face a common enemy that threatens both their worlds. This enemy could be a powerful Templar who has acquired some of the dark magic from Kratos' world.
The combat style of Assassin's Creed characters is more about stealth and quick, precise strikes. In a crossover, they could use their stealth to set up attacks for God of War characters like Kratos. Kratos, with his powerful and brutal attacks, could then finish off enemies. For example, an Assassin could sneak up on an enemy and stun it, allowing Kratos to deliver a fatal blow with his axe.
One of the most interesting aspects of a Perseus Jackson in God of War fanfiction could be his relationship with Kratos. Kratos is a complex and powerful character. Perseus, with his own set of values and beliefs, might either become an ally or an adversary to Kratos. They could learn from each other's combat styles and experiences, or they could be at odds due to their different views on the gods and their roles.
Arcanine. This majestic and powerful fire - type Pokemon has a look of a noble beast. In the God of War world, it could be seen as a symbol of power, like the mythical beasts there. It could use its fire attacks to fend off the hordes of demons and other enemies.
The most creative aspect is the character crossovers. Imagine Kratos teaching Kassandra some of his combat moves. It's a clash of different fighting styles and personalities.
One idea could be a crossover with Norse mythology outside of the God of War series. For example, Kratos could meet Thor from the original Norse tales. Another could be a crossover with Greek and Roman mythology, where Kratos encounters some of the forgotten or lesser - known Roman gods. Maybe a crossover with a popular fantasy world like Middle - earth, and Kratos has to face off against some of the powerful beings there.
One possible plot could be that Kurosaki Ichigo from Bleach somehow gets transported to the world of God of War. He might team up with Kratos. They could face off against a new threat that combines the Hollows from Bleach and the monsters of God of War. For example, Hollows with the strength and brutality of the Cyclops. Ichigo's Zanpakuto skills would be interesting to see combined with Kratos' brute force combat style.
A crossover with another popular action - adventure game like 'The Witcher'. Geralt and Kratos could meet in a world that is a blend of their two universes. They might initially be at odds due to their different moral compasses, but then find common ground in fighting a powerful, otherworldly enemy that neither could defeat alone. This would create an interesting dynamic between their combat styles and personalities.
Another possibility is that there is a new threat that emerges from the combination of the two universes. Some sort of evil entity that has the powers of both the Naruto universe, like the ability to use chakra, and the dark magic from the God of War world. Naruto and Kratos would have to learn to trust each other quickly in order to stand a chance against this new foe. They might start off at odds with each other due to their different backgrounds and fighting styles, but eventually realize that they need to work together.
A possible plotline could be a battle royale - style story where characters from both God of War and DxD are pitted against each other in a tournament. The winner gets some ultimate power or prize.