The plot could involve Ben using his alien forms to help the Young Justice team in their missions. For example, he could transform into Heatblast to deal with a fire - based villain that the team is struggling with. His alien powers would add a new dimension to the team's capabilities.
Ben would likely be the wild card. He'd be excited to show off his alien forms to the Young Justice characters. Aqualad might be a bit skeptical at first, but Robin could be intrigued by Ben's tech. Superboy might see Ben as a rival in terms of power.
One idea could be a crossover where Ben Tennyson ends up in the Young Justice universe. He could team up with the young heroes to fight a common enemy. Maybe a group of villains from both universes join forces, and Ben uses his Omnitrix to transform into different aliens to help in the battles.
First, you need to know both universes well. Research the characters, their powers, and the storylines in Ben 10 and Young Justice. This will help you create a believable crossover. For example, if you want to write about a fight scene between Ben and a Young Justice character, you should know their respective fighting styles and limits.
If Naruto joins Young Justice in fanfiction, he might introduce the concept of chakra to the team. This could open up new ways for them to develop their powers or enhance their existing abilities. He could also form interesting relationships with the characters. For example, his friendship with Robin could be based on their shared leadership qualities and intelligence. And his combat skills would make him a valuable asset in taking on powerful villains.
One possible plot could be Nightwing joining Young Justice as a mentor. He'd bring his years of experience from being Robin and working with Batman. He could train the young heroes in new combat techniques and also teach them about stealth and detective work.
Another fascinating plotline is when an ancient evil from Ben's world crosses over into the Young Justice universe. This forces both Ben and the Young Justice team to put aside their differences and combine their skills and powers to defeat this new threat. It usually involves a lot of research into both universes' mythologies, and the story can show how the two groups learn from each other and grow together as they face this powerful enemy.
Well, the plot could involve Ben Tennyson and the Young Justice team teaming up to fight a common enemy like Darkseid. Ben could use his various alien forms to complement the powers of the Young Justice members. For example, Heatblast could help Superboy when dealing with cold - based threats.
The combination of different powers. For example, seeing how Ben's alien forms interact with the superpowers of the Young Justice characters. It creates unique battle scenarios.
One idea could be to have Ben Tennyson end up in the Young Justice universe by accident. Maybe his Omnitrix malfunctions during a fight and transports him there. He could then team up with the Young Justice heroes to fight a common enemy like the Light or some new villain that's a threat to both universes.