Mega Man

The most superest fighting robot ever!

Mega Man is a surprisingly good friend toward the three other company mascots. Despite being loyal to Mario, he will go against him if it means potentially reviving his dead franchise. His feelings about Might No. 9 are unknown.

Plot
While the group were looking for recruits, they decided to look for Mega Man.

They found him in the Computer room, after he kicked Shadow and Vector out. No one knows what they were doing in there. Mega Man himself looked groggy, probably haven just woken up from a recharge nap. The group convince Mega Man to join by promising him with a possible future where his franchise isn't dead.

History
Sometime in the 21st Century... In an alternate timeline where literally everyone focused on improving technology where Back to the Future's future actually happened, Rock offered up to help stop Dr. Wiley. He stopped him like... What...? 5 times, even more? Well it was a lot. Then I'm pretty sure he tried to rebel or something so he had to be shut down.

After a soft reset thanks to Mario and Luigi, Mega Man finds himself in Capcom's dumpster. Robot tears streaming down his face after learning the truth, Mario offers him a place in the next Smash bros game. Heartfelt by the offer, Mega Man accepts, then saying "Thank you Mario, Luigi... But please, call me Rock. I'm no longer Mega Man, just a mere Robot."

Mario took poor Mega Man in and cared for him. Luigi also seems to like him to the point where he'd kick the shit out of the creator just to keep him.

Mario
Having known Mario since the NES days, Mega Man owes Mario for the start in his franchise, and his place in Smash. He'd not dare betray him, but he would team up with someone that promises another game if it meant his franchise would stay on life support.

Luigi
While not as close with Luigi as his brother, he seems more comfortable around him as opposed to acting like a Pupil or shy lower classman toward Mario.

Snake
Both have seemingly been through shit, but only one type of shit can break a character. Snake sees Mega Man as a comrade in arms and someone that needs support, while Mega Man sees him as surprisingly sympathetic and rather understanding. Not to mention their third-party status allows them to connect a lot more and be more thankful for what they've been given.