The vampires from Diabolik Lovers would likely be divided in their reactions. Some might see the characters from Frozen as mere prey, while others might be more interested in the magic and power that Elsa and Anna possess. There could be power struggles among the vampires as they debate what to do with the sisters. And the sisters would have to use their wits and Elsa's powers to survive in this new and dangerous world.
One idea could be that Elsa's ice powers attract the attention of the vampires in Diabolik Lovers. Maybe they see her as a unique being and try to either control her powers or use her for their own dark purposes. For example, one of the vampire brothers might think that her ice could be used to create a new kind of weapon or to enhance their lair's defenses.
Anna, being outgoing and adventurous, would probably get along great with Chat Noir. They could have a lot of fun banter and adventures together. When it comes to Elsa and Hawk Moth, Elsa's coldness (in personality as well as power) would be a contrast to Hawk Moth's manipulative and power - hungry nature. She would be very resistant to his attempts to use her for his evil plans.
The characters would likely have a mix of admiration and friendly rivalry. For example, the cool and collected protagonist of Persona 5 might be intrigued by the more laid - back nature of the Persona 4 protagonist. Meanwhile, the Persona 3 protagonist, with his more somber and serious demeanor, could initially seem a bit intimidating to the others. But as they get to know each other, they would start to bond over their shared experiences of fighting Shadows and protecting their worlds.
The 1987 Turtles would probably be very curious about the more serious and intense 2003 Turtles. They might crack jokes at first to ease the tension, while the 2003 Turtles could be a bit annoyed by their silliness. But as they face challenges together, they'd start to respect each other. For example, when fighting Foot Soldiers, the 1987 Turtles' acrobatic and fun - loving fighting style could complement the 2003 Turtles' more strategic and brutal combat.
First, decide which other universe you want to cross it with. Then, research both the Diabolik Lovers world and the other world thoroughly. For example, if you choose a crossover with Naruto, understand the ninja system, the clans, and how chakra works. Next, create a plot that brings the two worlds together in a believable way. It could be something like a portal opening between the two worlds. After that, introduce the characters from both universes and start developing their relationships. Don't be afraid to put your own spin on the characters' personalities.
The characters' interactions would be really interesting. Elsa, with her calm and powerful demeanor, would likely be cautious around Tarzan and his world. However, as she sees how he is in harmony with nature, she might start to respect him more. Anna, on the other hand, would be very enthusiastic and would try to communicate with the animals right away. Tarzan would be both intrigued and perhaps a bit confused by their foreign ways. He might teach them about jungle survival, while they could teach him about their kingdom and family bonds.
In a crossover, the RWBY characters would have to adapt to Doflamingo's powers. Yang's hot - tempered nature might lead her to engage in a direct fight with Doflamingo, which could be both dangerous and exciting. Weiss would use her intelligence and her family's resources to try to find a weakness in Doflamingo. Ruby, with her innocent yet determined personality, would try to find a way to redeem Doflamingo if possible, but if not, she'd be fully committed to taking him down.
The Naruto characters are used to a world of ninjastic and chakra - based powers. When they meet the Claymore characters, who have a different set of powers based on their yoma - human nature, there would be initial confusion. For example, Naruto might be very curious about the Claymore swords and how they are used. The Claymore characters, like Clare, would be cautious about Naruto's exuberant personality and his powerful chakra. But eventually, they could learn from each other. Naruto could teach them about teamwork in a different way than they are used to in the Claymore world, and the Claymores could show Naruto how to be more stealthy and precise like they are when hunting yoma.
Sasuke from Naruto might initially be distrustful of Lucifer. He's used to dealing with his own world's threats and Lucifer's devilish appearance and powers would make him cautious. But if they find a common goal, like protecting someone or something, Sasuke could grudgingly work with him. Naruto, on the other hand, would be more open - minded and try to befriend Lucifer right away.
Sakura from Naruto and Masane from Witchblade could have an interesting interaction. Sakura, being a strong - willed and skilled medical ninja, might be intrigued by Masane's connection to the Witchblade. She could try to study it from a medical perspective. And Masane could teach Sakura some new combat moves that are more brutal and less refined than the ninja techniques Sakura is used to.