Mega Man creator Keiji Inafune had a say about including Mega Man in Street Fighter X Tekken. "I consulted with Mr. Megaman(his name is Mr.I…) about it 1 years ago. It’s [a] result," producer Yoshinori Ono tweeted to a fan asking why Bad Box Art Mega Man was selected for the fighting game.
And it appears Bad Box Art Mega Man is a nod to Mega Man Legends. Just check out his character profile.
Known as a Digger, a person who digs up relics from the past for research. He is a hot-tempered man, but has a strong sense of justice and is also very polite. His weak point is that he is easily rattled when backed into a corner. He is always running around in a hurry due to the demands of his partner Roll, and this time he’s been asked to travel to Antarctica to retrieve a mysterious box.
A living being whose origin and motive are wrapped in mystery. It is an omnivorous life form that consumes anything in its path. No matter what happens, its smile never leaves its face. It is not known what it is thinking or what its motives are, but it is certainly heading towards the box.
Wait… Roll? Really curious to see what she looks like in Street Fighter X Tekken.