Archaon could be an amazing character to feature. His role as the Everchosen of Chaos would bring a lot of chaos (pun intended) to crossovers. Alarielle, the Everqueen of the high elves, with her beauty and power, would be a popular pick. Also, Gotrek Gurnisson. His dwarven stubbornness and his quest for a glorious death could create some really engaging storylines when combined with characters from other universes.
Sigmar is a great choice. His heroic and god - like status in Warhammer Fantasy could make for interesting interactions in a crossover. Another is Malekith. His dark and complex nature would add depth to crossovers, especially with darker - themed universes. Then there's Teclis, the high elf mage. His powerful magic could be a key element when crossing over with other magic - heavy worlds.
The Space Marines are often popular. Their super - human abilities and cool armor make them great for crossovers. They can be paired with characters from other universes and show off their combat prowess. Another popular character is Abaddon the Despoiler. His menacing presence and leadership in the Chaos forces can create some intense crossover storylines.
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.
Archaon is often a popular choice. His dark and powerful presence can add a lot of drama to a crossover story. He could be pitted against heroes from other factions in unexpected scenarios.
The Space Marines from Warhammer 40k are often popular. Their super - human strength and combat skills would make for an interesting match against the various alien species in Mass Effect. Commander Shepard from Mass Effect is also a common choice. His/her leadership and combat abilities could be a great addition to the often dark and gritty Warhammer 40k universe.
The IMC soldiers can also be great for crossovers. They have their own set of skills and motives. In a crossover with a stealth - based game universe, the IMC soldiers' combat tactics and equipment could add an element of intrigue.
Alya is also a great character to feature. Her intelligence and strategic thinking can be useful in different crossover scenarios. If crossed over with a science - fiction world, she could be involved in advanced technological research or battles against alien invaders.
Wonder Woman is an obvious choice as she is from Themyscira. She can be paired with characters from other universes like Superman for a DC crossover. In a crossover with the 'X - Men' universe, she could interact with Storm, two powerful female characters with different abilities. Another popular character would be Hippolyta. She could be involved in a crossover where she has to negotiate with leaders from other fictional kingdoms or planets.
Definitely Maurecia. She's got such a fun and unpredictable personality that she can bring a lot of energy to a crossover. Todd would also be great as he's often the 'normal' one in the Wayside chaos, so seeing him interact with characters from other worlds could be really interesting. And let's not forget Mrs. Jewls, who could use her wisdom and authority in a crossover situation to keep things in order or add some comical misunderstandings.
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.
Rainbow Dash is also popular. Her athleticism and bold personality can create interesting dynamics. In a crossover with the Teen Titans, she could compete with Robin in a series of challenges, or team up with Starfire to take on a common enemy.