Pharah and a Titanfall scientist. Pharah is a highly trained soldier with a focus on aerial combat. A Titanfall scientist might be researching new ways to improve Titan mobility or weaponry. Their alliance could be born out of a need to create some new kind of weapon or technology. The scientist could use Pharah's combat knowledge to better understand how their creations will be used in actual battles, and Pharah could get access to some really advanced tech.
A crossover could involve the characters swapping abilities. Imagine Tracer from Overwatch having the ability to call in a Titan like in Titanfall 2. Or a Titanfall 2 pilot having the ability to use some of the support abilities of the Overwatch heroes, like Mercy's healing. This would create really interesting and unique combinations in combat scenarios.
A really interesting storyline could be centered around the conflict between the two factions in Titanfall and how the Overwatch heroes get involved. Maybe the Omnics from Overwatch are somehow related to the IMC or the Militia in Titanfall. This would lead to a complex web of relationships and battles. The Overwatch heroes would have to adapt to the Titanfall combat style, and the Titan pilots would learn to work with these new, diverse heroes.
The plot could center around a new threat that only the combined forces of Titanfall 2 and Overwatch can defeat. For instance, a powerful alien race that has the ability to disrupt technology, which affects both the high - tech Titans and the various advanced weapons and gadgets in the Overwatch universe. So, heroes from both sides must put aside their differences and fight together.
Reaper and Deadpool would be a hilarious and action - packed combination. Deadpool's non - stop talking and crazy antics would contrast with Reaper's brooding and serious nature. They could be on a mission to take down a target that has ties to both Talon and some Marvel villains. And Pharah and Falcon would also be great together. Their aerial combat abilities would be amazing to see combined, and they could bond over their shared love for flying and protecting their respective worlds.
Reinhardt and Yang would be an interesting pair. Reinhardt is an old - fashioned knight, full of honor and valor. Yang is a tough fighter with a bit of a hot - tempered side. They would likely start off butting heads as their personalities are quite different. But as they train together or face a common enemy, they would come to respect each other. Yang could learn about the code of chivalry from Reinhardt, and Reinhardt would be impressed by Yang's raw strength and her ability to keep fighting even when outnumbered.
Winston and All Might would be a powerful duo. Winston's strength as a gorilla - like hero in Overwatch, especially when he goes into his Primal Rage, combined with All Might's Symbol of Peace status and his incredible strength in My Hero Academia. They could inspire those around them while also being a force to be reckoned with on the battlefield, and their leadership qualities could help to guide the combined forces of the two universes.
For the Infamous side, Cole MacGrath would be a likely candidate. His powerful electrical abilities would make for an interesting dynamic in the Overwatch universe. On the Overwatch side, Tracer would be a great fit. Her speed and agility could contrast with Cole's more brute - force power. Also, Reinhardt could be involved. His chivalrous and protective nature would be interesting to see interacting with the Infamous characters.
Mercy from Overwatch and the Medic from TF2 could be the first to interact. Given their roles as healers, they would likely be interested in each other's medical techniques. They might start by comparing notes on how to heal their comrades more effectively, and this could lead to a deeper understanding and cooperation between the two groups.
Akira and Giorno would make an interesting pairing. Akira has his leadership skills and the ability to use Personas, while Giorno has his determination and powerful Stand, Gold Experience. They could learn from each other's sense of justice and different ways of achieving their goals. Akira could teach Giorno about the power of the collective, as the Phantom Thieves work as a team, and Giorno could show Akira how to be more assertive and decisive in his actions.
I think Kakashi and Genie from 'Aladdin' would make an amazing combination. Kakashi is always mysterious with his covered - up eye and his vast knowledge of ninjutsu. Genie, on the other hand, is full of magic and humor. Genie could use his magic to play pranks on Kakashi, and Kakashi could try to teach Genie some ninja moves. And then there's Ino and Ariel. Ino's strong - willed and confident personality paired with Ariel's curiosity about the human world could create some really fun and engaging interactions.