One common theme is the clash of values. Naruto comes from a world where friendship and perseverance are highly valued, while Berserk has a much darker and more cynical view of the world. So, in these fanfics, you often see Naruto trying to uphold his values in the face of Berserk's harsh reality.
One idea could be that Guts from Berserk is somehow transported to the Naruto universe. He could encounter Naruto and his friends. Maybe they initially mistake him for an enemy because of his intimidating appearance and weaponry. But as they get to know him, they realize his noble heart and his fight against the forces of evil in his own world, and they team up to face a common threat in the Naruto world.
One popular 'naruto berserk crossover fanfic' might be 'The Ninja of Midland'. In this fic, Naruto is somehow transported to the Berserk universe. He has to adapt to the dark and gritty world while still holding onto his ninja values. It's a really interesting read as it shows how Naruto's positive attitude clashes with the often hopeless and cruel world of Berserk.
One common theme is the clash of different power systems. For example, when Berserk crosses with a series like 'Naruto', the magic and brute strength in Berserk contrast with the chakra - based powers in Naruto. Another theme is the exploration of different moral compasses. Characters from Berserk, which has a rather dark view of the world, interact with characters from more idealistic series, leading to interesting moral debates.
It could be Orochimaru. He's always been interested in Naruto's power. He might use some new jutsu or experiment on Naruto to make him go berserk so he can study his power in that state.
One possible plot could be that Guts from Berserk is somehow transported to the Naruto universe. He might initially be seen as a threat due to his menacing appearance and his large sword. However, as the story progresses, he could team up with Naruto and his friends to fight against a common enemy, like an Akatsuki member who has acquired some of the dark magic from the Berserk world. Guts' fighting skills and his ability to face the most terrifying foes could inspire Naruto and give him new perspectives on combat.
Well, in a naruto and berserk crossover fanfiction, the characters could interact in many ways. One way is through cultural exchange. Naruto and his friends could introduce the Berserk characters to the concept of ninja villages, chakra, and the shinobi way. In return, the Berserk characters could share their knowledge of medieval - like warfare, their complex political systems, and their understanding of different forms of magic. This exchange could lead to new friendships and alliances. For instance, Sakura could learn some sword - fighting techniques from Guts, while Guts could learn about medical ninjutsu from her. Also, the more morally ambiguous characters from Berserk, like Griffith, could interact with the shinobi in ways that test their moral compasses. His grand plans and manipulative nature could cause conflict among the Naruto characters, leading to interesting character development for both sides.
A unique feature is the blend of the two different art styles. Naruto has a more traditional shonen art style, while Berserk is known for its detailed and often darker, more mature art. In the fanfic, this can translate to a different visual experience in the reader's mind. For example, Naruto's spiky hair might be combined with the more detailed and menacing look of Berserk characters.
Another great one is the berserk crossover with 'One Piece'. Here, the contrast between the high - seas adventure and swashbuckling fun of One Piece and the dark, brutal world of Berserk makes for a very unique reading experience. The different power systems and character personalities collide in unexpected ways.
Another interesting concept is to have the characters from Berserk interact with the magical creatures and races of the kingdom. The Band of the Hawk could be hired as mercenaries by the kingdom to fight off an invasion of some sort. This would lead to some great action scenes and also allow for character development as they interact with the new and different people of the kingdom.