Master Chief is definitely one of the most popular. He's the face of the Halo series, so fans love to see him in crossovers. Cortana is also a popular choice. Her complex character and her relationship with Master Chief make for interesting crossovers. The Arbiter is another character that often features. His unique backstory and his role in the Halo universe can add a lot to a crossover story.
In Halo Warhammer 40k crossover fanfiction, the Librarians from Warhammer 40k are quite popular. Their psychic powers can lead to some really cool interactions with Halo's technology and characters. They can sense things in the Warp, and how would that work when dealing with the more scientific Halo universe? Cortana from Halo is also a favorite. Her artificial intelligence is something that doesn't really exist in the same way in Warhammer 40k. So seeing her interact with the various tech - priests or even daemon - possessed entities could be really interesting. Additionally, Chaos Space Marines are often used for their menacing and unpredictable nature in crossovers.
One character that is often used is Cortana from Halo. Her intelligence and relationship with Master Chief can be a great addition to a crossover. In the Starcraft universe, she could interact with the AI units there. Then there's Fenix from Starcraft. His honor - bound nature and combat prowess would be cool to see in the Halo setting. Also, the Flood-infected characters in Halo could be a unique addition to a Starcraft crossover. They could pose a new kind of threat to the Starcraft races, and seeing how the different factions deal with them would be engaging.
Master Chief is often a very popular character in Halo crossover fanfiction. His iconic status and combat skills make him a natural fit for crossovers. Writers like to put him in different scenarios and see how he reacts.
Definitely Master Chief. His stoic nature and combat skills would be really interesting to pair with Pokemon. He could be a silent but effective Pokemon trainer. Another would be Cortana. Her intelligence could be used to analyze Pokemon abilities and strategies. And of course, Pikachu would be a great character to include. It could be fun to see how it interacts with the Halo characters and technology.
John Koenig is often a popular choice. His leadership skills and complex character make him a great fit for crossovers. He can interact with other strong leaders from different sci - fi shows and create interesting power struggles or alliances.
Monika is often a popular choice. Her strong - willed and somewhat controlling nature can make for interesting crossovers. She can be the one who tries to manipulate the new world or characters she's crossed into. Sayori is also popular. Her bubbly and at times sad nature can add a lot of emotional depth to crossovers, especially in more light - hearted or heart - wrenching scenarios.
Loki is often a popular choice. His ability to deceive and his stealth capabilities can create really interesting plotlines in crossovers. For example, if crossed over with a detective - themed universe, Loki could be the elusive criminal that the detective characters are trying to catch, using his Warframe skills to outwit them.
Ikaris is often a popular choice. His flight and laser - eye powers make him a formidable character in crossovers. He can easily be paired with other flying superheroes or those who can withstand his powerful attacks. Sersi is also popular. Her ability to transmute matter gives her a unique edge, and she can be interestingly paired with characters who have different elemental powers.
Spyro is always a popular choice. He's one of the most well - known Skylanders and has a rich backstory that can be easily incorporated into crossovers. For example, he could be the leader of a group of Skylanders from different areas coming together.
Krawk is a popular character. It has a cool and somewhat menacing appearance which can add an interesting dynamic in crossovers. Another is the Shoyru. It's dragon - like and can bring a sense of magic and power. The Lupe is also often used. It has a wolf - like appearance and can be portrayed as a fierce and loyal character in crossovers.