Oh Jesus, why did you have to remind me of that abomination of both a game and representation of both Pac-Man and Megaman. I think I might vomit now.
Interestingly enough, he was a Playstation exclusive character. Also, it was actually well over two years between the release of SFxTK before Smash 4 came out, so it is possible that there were some exclusivity rights in regards to SFxTK, but at the same time...it's a crossover game featuring Namco, so it REALLY doesn't fall under this at all.
Remember, the thing to meet is: A character who is not Ryu or Terry (I would almost count Heihachi in this as well, but he hasn't been a guest character all that much), who is not part of a game who's base design is around a crossover of different companies, that has shown up in different games by different companies without an expansive amount of time in between appearances.
I can't speak for Fatman here, but my argument has always excluded crossover games like MvC, SFxTK, Blazblue Cross-Tag Battle and CvS.
Ahem. Right after Pac-Man Heihachi is Namco's crossover king.
Here is a list of his appeareances:
- Obviously every game in his Tekken series
- Optional boss in the Tekken spin-off Death by Degrees
- guest character in Soul Calibur 2
- guest character in Playstation All-Stars Battle Royale
- one of the many Tekken characters in Street Fighter x Tekken
- appeared in The King of Fighters: All Stars mobile game
- is one of the characters in Namco x Capcom
- one of the many Namco characters in Project X Zone and Project X Zone 2
- a guest character in Pro Baseball Famista 2011
- one of the many characters in Full Bokko Heroes X
- he is a playable character in Anna Kournikova's Smash Court Tennis, where he can play tennis against real life tennis players in simulations of real tennis championships!
- also playable in the sequel Smash Court Tennis Pro Tournament 2, it's funny to see him there playing tennis, if you know how he is in Tekken:
https://youtu.be/VEWQIz-PS4g
- is a narrator in Ridge Racer 6
- he is a character in Pac-Man-Fever
- he is one of Anise's dolls in Tales of the Abyss
- a mii costume in Smash 4
- as an 8bit sprite in Galaga: Tekken Edition
- that same sprite makes an appeareance in Smash Ultimate Pac-Man's namco roulette as a cameo
A playable appeareance in Smash would be the last missing achievement, but that will definitely follow soon too! Heihachi is destined to appear in Smash!