Worldwide the Super Smash Brothers series is about to become the best selling video game fighting series of all time.
Currently:
#1 - Tekken at 47 million between all titles.
#2 - Street Fighter at 41 million between all titles.
#3 - Super Smash Bros. at 40 million between all titles pre-Ultimate.
#4 - Mortal Kombat at 35 million between all titles.
https://en.wikipedia.org/wiki/List_of_best-selling_video_game_franchises