Another possibility is a more comical crossover. The Flash tries to race a Warthog from Halo and fails miserably because he doesn't understand the vehicle's controls. Or Batman trying to figure out the technology of Halo's weapons and getting all confused. This kind of fanfic would be full of humorous moments and cultural clashes between the two universes.
One idea could be that the Covenant from Halo discovers Earth while the Justice League is busy dealing with a local threat. The League has to quickly adapt to this new alien threat that has far more advanced technology than most of their foes. They might have to team up with Master Chief, who is also on a mission to stop the Covenant's invasion plans.
Character development is key. If you're writing a fanfic about this crossover, you need to make sure the characters from both universes stay true to their original personalities while also evolving in the new situation. For instance, Wonder Woman should still be strong - willed and brave when she meets the Arbiter from Halo.
Definitely Superman and Master Chief. Superman has all his superpowers like super strength, flight, and heat vision, while Master Chief is a highly trained super - soldier. They could have an interesting dynamic, with Superman respecting Chief's combat skills and Chief being in awe of Superman's powers. They could work together to take on powerful enemies, like Darkseid if he somehow got involved in the Halo - Justice League crossover.
Well, it really depends on what you consider 'good'. There could be some really creative ones where the Justice League characters are watching events from the Halo universe. However, the quality can vary greatly. Some might be well - written with great character interactions, while others might be more of a quick, fun read with not as much depth. You'll have to dig through a bit to find the ones that suit your taste.
One idea could be that Tsunade is brought to the Justice League's universe through some sort of magical portal mishap. She could use her medical ninjutsu skills to help treat injured Justice League members, like when Superman gets hurt by a kryptonite - based weapon. Her tough - as - nails attitude would also make for some interesting interactions with Batman, who might be intrigued by her no - nonsense approach.
In a fanfiction, the Ghost Rider could form an alliance with Batman. Batman would be intrigued by the supernatural element that Ghost Rider brings. They could team up to take on villains who are using magic or other dark forces. Ghost Rider's powers of hellfire and his unearthly strength would be a great asset to the Dark Knight's strategic mind.
In a strange turn of events, a portal opened up and Vegeta found himself in Gotham City, home of Batman. Vegeta was confused but ready for a fight. Batman, always cautious, observed Vegeta. Eventually, Batman convinced Vegeta that there was a greater threat that required their combined efforts. The Justice League, including Wonder Woman, Flash, and Aquaman, joined them. Vegeta was impressed by their diverse abilities. During the battle against a mind - controlling villain, Vegeta's brute strength and the Justice League's strategic planning worked in harmony. Vegeta learned about teamwork from the League, and they all respected his warrior spirit in the end.
Tsunade would have an interesting dynamic with Wonder Woman. They are both strong female characters. Wonder Woman would likely respect Tsunade's leadership skills and combat abilities. Tsunade, on the other hand, might be impressed by Wonder Woman's god - like powers.
In a Young Justice and Justice League crossover fanfiction, character development can occur in multiple ways. Firstly, the less - experienced Young Justice members can learn from the Justice League's vast knowledge and experience. A character like Robin in Young Justice could gain new insights into detective work from Batman. On the other hand, the Justice League members can be inspired by the Young Justice team's energy and fresh perspectives. Superman might see the determination of a young hero like Superboy and start to reevaluate his own approach to heroism. Also, characters can develop through shared traumas. If they face a particularly difficult villain who causes a lot of destruction, they might all grow in their empathy and understanding of the importance of protecting civilians.