In a Prototype - Mass Effect crossover fanfiction, a possible scenario is that the Reapers from Mass Effect encounter Mercer. Since Mercer can consume and assimilate other beings, it would be interesting to see how he'd fare against the Reapers. He might be able to absorb some of their technology or even gain new powers from them. And the way the different races in Mass Effect, like the Turians or Asari, would react to his presence would also be a great plot point.
A great concept could be a story where the Prototype technology is somehow introduced into the Mass Effect universe. For example, some Cerberus scientists could get their hands on Prototype samples and start experimenting. This could lead to the creation of new, dangerous hybrids that the main characters have to deal with. Or perhaps Shepard has to team up with a character similar to Mercer to fight a common enemy that is exploiting both Prototype and Mass Effect technologies.
If a character like Miranda Lawson from Mass Effect met Mercer, she would probably be fascinated by his biological makeup. She might try to analyze him from a scientific perspective, which Mercer may or may not tolerate. And when it comes to combat, Mercer could provide a new and unexpected element to the fight. For example, he could use his shape - shifting to surprise enemies while the Mass Effect characters use their biotics and tech. Also, the loyalty and morality of the Mass Effect characters could have an impact on Mercer. He might start to question his own actions and motives in the face of their strong beliefs.
Alex Mercer would be the most interesting. His abilities are so unique. In the Mass Effect universe, he could completely disrupt the power balance. He can shapeshift into anyone, which means he could infiltrate the Citadel Council or any other important organization with ease. His superhuman strength and regenerative abilities would also make him a formidable force against the enemies in Mass Effect, like the Collectors or the Reapers.
One great 'Mass Effect' crossover fanfiction is 'Mass Effect and Star Wars: The Galactic Alliance'. It combines the rich lore of both universes in an exciting way, with characters from 'Mass Effect' interacting with those from 'Star Wars'. Another is 'Mass Effect meets Warhammer 40K', which creates a really unique and action - packed story as the two very different sci - fi settings collide. There's also 'Mass Effect and Halo: The United Front' that has some really interesting character dynamics between the heroes of the three franchises.
One great 'Fallout Mass Effect Crossover Fanfiction' is 'The Wasteland Beyond the Stars'. It combines the post - apocalyptic feel of Fallout with the space - faring adventure of Mass Effect really well. The main character from Fallout somehow gets transported to the Mass Effect universe and has to adapt to the new technology and politics there.
Well, Master Chief would likely start by assessing the threats in the Mass Effect universe. He'd notice the Reapers right away as a major threat. His military training would kick in, and he'd try to find ways to combat them. In terms of adaptation, he'd probably look for allies. He might be initially skeptical of the alien species but would soon realize that they can be valuable partners. For instance, he could team up with the Turians, who also have a strong military tradition. He'd also have to adapt to the different forms of transportation, like the Mass Effect relays. His first encounter with using one of these relays might be a bit of a shock, but he'd quickly figure out how to use it to his advantage.
One common theme is the clash of different cultures. The very different races in Warhammer and Mass Effect coming together often leads to interesting cultural exchanges and conflicts.
Another theme is technological exchange. The advanced technologies in both universes are often explored in these fanfictions. For instance, the biotics in Mass Effect and the psionic powers in Starcraft could be combined or compared. Sometimes, the fanfictions explore how sharing technology could change the balance of power in both galaxies. It can lead to really exciting plot developments as characters try to figure out how to use newfound tech or prevent others from getting their hands on it.
A great Mass Effect Shepard crossover fanfiction often has a well - written Shepard. The character should stay true to their in - game personality while also adapting to the new crossover situation. For example, if it's a crossover with Star Wars, Shepard's leadership skills should be shown in a way that makes sense in the Star Wars universe. Good world - building is also key. If it's a crossover with a different sci - fi or fantasy world, the author needs to blend the two worlds seamlessly.