Marvel's Chris Baker said the process involved quite a bit of back and forth and weighed everything from a character's fighting style and potential special attacks to his or her popularity and even physical height.
"We are very involved in character selection," said Baker, who helps to oversee Marvel licensing for video games. "Very early on (Capcom) came to us and said we would like to use these characters. We took a look at the list. Almost all of the choices they had are great, they know the characters very well."
But, Baker said, there were a lot of things to keep in mind when filling out that roster.
"The basis for character selection in any fighting game is a nice balance of this guy is a brute, this guy is really scrappy, this guy shoots laser beams," Baker said. "Making sure you have all sorts of variety, different sizes of characters and then looking at popularity and relevance. And then there are some characters you may not necessarily think of right away that just lend themselves really well to a fighting game."
So Marvel, scouring through their more than 5000 characters, went back to Marvel with some of their own choices.
Baker was very coy in talking with Kotaku about who might or might not make the final cut for the game. He did tell us that the roster, while nearing completion, is still not finalised. He also explained some of the things that Marvel looks at when deciding which sorts of characters they would want in a game.
"There are absolutely characters that will be much more relevant in the next few years and you want to get them in there," Baker said. "There are characters that have become a lot more popular since the last Marvel Vs Capcom game, that weren't in there that we wanted to get in there. There are characters that have been invented in the last ten years that we may want to get in there."
While I wasn't able to squeeze any more names of characters out of Baker, he hinted that more names would be coming in the next few months.
"Think of upcoming gaming and comic events," he said. "We have a year and want to keep you interested, but I don't think the news will be coming one character at a time."
After much browbeating I was able to half-confirm one character who likely won't be in the game: Lady Bova. That's right, Scarlet Witch's cow nanny won't be a "core character" in the game.
Once a character makes the cut, Capcom begins working up how they will look in the game, another tricky process that included a lot of Marvel feedback.
"My job is to ensure that the characters are in line with what they should be at a very base level," Baker said. "Making sure that their looks are modern."
For example, Marvel Vs Capcom 3's Wolverine is a much different beast than the Wolverine of the last Marvel Vs Capcom game. In Marvel Vs Capcom 2, Wolverine had what Baker described as a "'90s look" with exaggerated "ear things" and impractical boots.
"Now his costume plays down the ear thing, the boots are more practical, but it's still the classic yellow and blue costume everyone loves," Baker said. "So basically our job is to kind of steer them in that direction: 'This is what we are doing with the characters now (in comics), this is how we want you to present it in the game.'"
The Hulk, Baker said, is a character design very much born of Capcom's "artistry".
"Their Hulk is pretty unique," he said. "There are definitely issues of comics you could compare him to. He may not look like the Hulk of today, but that's OK."
Once a character's base look is nailed down the two teams begin work on figuring out the character's moves and special attacks.
"They do all of the mechanics, we're not game developers at Marvel we are the licensors, we know our games but it's Capcom that is developing this game," Baker said. "Fortunately, they do their research and they generally know their characters very well. Every once in awhile there will be a special move that's like, 'Hmm, maybe you should change that to this.' Or maybe they are leaving out a really great move that we think should be in there.
"That's why we are here, to make sure Wolverine isn't shooting lasers out of his claws, to use an extreme example."