The main characters are Naruto and Jack, but the fanfiction could also introduce new characters that are a blend of the two universes. For example, there could be a character who has both chakra - like Naruto - and biotic abilities - like Jack. This new character could be the result of some experiment gone wrong or a natural occurrence in the combined universe of the fanfiction. And of course, there would be various antagonists, such as the usual bad guys from the Mass Effect universe who see Naruto as an unknown and dangerous variable, and perhaps some of Naruto's enemies from his own world who have also found their way into the Mass Effect universe.
One possible plot could be that Naruto, through some sort of interdimensional rift, ends up in the Mass Effect universe and teams up with Jack. They might use Naruto's ninja skills and Jack's biotic powers to fight against a common enemy, like a new Reaper threat or a rogue Cerberus group.
Shepard could be one of the main characters. Imagine Shepard having to deal with Venom's presence. Shepard's leadership skills would be put to the test as they try to figure out if Venom is a threat or an ally. Also, Garrus could be involved. His combat skills and loyalty to Shepard would make for some interesting interactions with Venom.
Shepard from Mass Effect is often a popular character. Writers might like to put Shepard in the Naruto universe and see how his or her leadership skills play out among the ninja. Also, Naruto himself is obviously a central figure and seeing his reaction to the Mass Effect elements can be really engaging.
A great one often has well - developed characters. The OC should have a unique personality and backstory that fits within the Mass Effect universe. The relationship between the OC and Jack should be believable and grow over the course of the story. Good writing quality, with proper grammar and spelling, also helps a lot.
The main themes can vary. But often there's the exploration of identity. Naruto and Jane both have strong identities from their original stories. In the fanfiction, they might question or redefine themselves in the context of this crossover. Another theme could be the search for purpose. They may find new goals in this combined universe, whether it's saving a planet or uncovering a mystery. And the theme of loyalty, to their new friends and to their own values, is also likely to be present.
There might be a human scientist who is at the forefront of some revolutionary discovery. This character could be trying to unlock the secrets of an ancient alien technology that has the potential to change the course of humanity's future in the fanfiction.
It could be a mix of characters from both universes. There might be classic WW2 soldiers like Patton or Eisenhower, but with a Mass Effect twist. Maybe they have some kind of exposure to Mass Effect technology that gives them special abilities. Also, there could be Mass Effect characters like Shepard who are somehow transported to the WW2 era.
Obviously, Tevos is a main character. She's a significant figure in the Asari government. And then there are the OCs (original characters). These can be a wide variety of beings. It could be a human soldier who gets involved in Asari politics because of some incident related to Tevos. Or an alien scientist who teams up with Tevos to study an ancient Prothean relic. Each OC brings their own backstory, skills, and motives to the story.
Master Chief from Halo is also a common character in these crossovers. His super - soldier abilities and stoic personality could make for some interesting interactions with the more diverse cast of Mass Effect. He might be intrigued by the biotics or the different political systems in the Mass Effect galaxy.
Shepard from Mass Effect often shows up in these crossovers. Because Shepard is such a well - known and strong character, it's easy to put them in the Warcraft universe and see how they interact with the likes of Thrall or Jaina.