They could go on a quest to find a lost magical artifact. Maybe it's a powerful weapon that was hidden long ago to prevent misuse. Percy's skills in water combat and Leo's mechanical genius would be very useful. For example, if they come across a flooded cave where the artifact is hidden, Percy can navigate through the water while Leo figures out how to bypass any mechanical traps.
They could have an adventure exploring the Forbidden Forest. Dudley, being curious about Harry's world, could tag along with Harry. They might encounter magical creatures like centaurs or unicorns. Dudley would be in awe and a bit scared at first, but with Harry's guidance, they could learn about these creatures and even help one in need, like a unicorn caught in a trap. This adventure would strengthen their friendship as they rely on each other in the forest.
They could go on an adventure to explore the hidden secrets of the ninja world. Maybe there are ancient ruins that hold the key to a powerful jutsu, and Naruto and Kyuubi work together to uncover it. Naruto uses his ninja skills and Kyuubi provides the necessary power boost when needed.
Maybe they go on a journey to find a lost artifact that has the power to control both vampires and demigods. Along the way, they face various challenges like werewolves who don't want them to succeed and demigod enemies who see Bella as a threat. Percy would use her strategic thinking from her demigod training, and Bella would rely on her instincts from living in the vampire world.
Well, they could embark on a journey to explore an ancient ninja ruin. Naruto, with his curiosity, would be eager to discover new things, and Tenten, being knowledgeable about ninja history related to weapons and artifacts, could guide them. Along the way, they'd face various challenges and grow closer as friends.
Well, they could have an adventure in a new dimension. Naruto's ability to use chakra and Gohan's ki powers could be combined in unique ways. For example, they could use their combined energy to break through barriers that are otherwise impossible to cross. And they would surely make new friends and enemies in this new dimension.
They could have an adventure in an enchanted forest. Maybe they get lost and have to use Percy's skills with water to find a way out, like creating a stream that leads them to safety while Piper uses her charm - speaking to communicate with the forest animals for directions.
They could have an adventure in an ancient, forgotten temple. Maybe they are on a quest to find a lost artifact that could save their world. Along the way, they use Percy's water powers and Annabeth's strategic mind to overcome various traps and monsters.
One possible adventure could be in the Underworld. Percy had some experience there already, and Artemis, with her fearless nature, accompanied him. They went to rescue a lost soul that was important to both of them. Along the way, they had to face the challenges of the Underworld, like getting past Cerberus and dealing with the tricky spirits that tried to deceive them. Their friendship was tested as they made their way through the dark and dangerous realm.
They could go on an adventure to save a shared realm. Maybe there is a third world that is being corrupted by a new, unknown force. Elsa's ice powers and Pitch Black's control over nightmares could be combined in an unexpected way to fight this new threat. For example, Elsa could freeze the physical manifestations of the nightmares while Pitch Black could use his knowledge of the dark to find the source of the corruption.
Well, they could embark on a journey to find other tailed beasts and try to form a new kind of bond among them. This would be an adventure full of challenges as some of the tailed beasts might be hostile at first. Naruto and Kyuubi, as brothers, would use their combined strength and Naruto's persuasion skills to make peace with them. Along the way, they would also learn more about each other's capabilities and grow closer as brothers.