Out of Curiosity, I thought I'd look at he series represented in Super Smash Bros Ultimate and see how they relate to the sales of their respective games.

To clarify, I'm only including Nintendo series, and am also excluding Game & Watch due to the abnormal nature of that series. Also, I couldn't find any conclusive numbers for the Mario series, so I left it with a slightly outdated total of 600 million sales.

A few things to note:

• Fire Emblem is NOT the series with the most fighters considering its sales. It is only third place. Earthbound/Mother has the largest proportion of reps, followed by Kid Icarus.
• Despite their massive rosters of fighters, Mario and Pokemon arguably deserve more fighters based on the ratio. Mario affiliated series such as Yoshi, Donkey Kong, and Wario also err towards the side of having too few fighters representing them.
• There is no general rule considering series with a single representative. Some, like Ice Climber and R.O.B.'s Robot series, come from relatively minor franchises. Others, like F-Zero and Splatoon, are somewhat significant series in their own right. And a few, like Duck Hunt and Wii Fit, arguably deserve more reps.
• If we did include Game & Watch as a series, it would be on par with Wii Fit in terms of having lots of sales despite a lack of reps.
• How long a series has been appearing in the series seems to have only marginal impact. Mario and Pokemon have been around since the N64 entry, but their top competitors, Wii Fit and Duck Hunt, were only introduced in SSB4.

This is interesting, but I really don't like this idea that Smash reps should be based on series sales. I don't think you were implying that, just saying. Also, Pokemon and Mario arguably deserve more reps, but not because of their sales. It's because they have a lot of iconic gaming characters. I think Paper Mario should get his day sometime! And of course, Pokemon is always going to justify a Smash rep since a new popular game is always coming out.

We really need a Zelda rep that isn't some form of the three most relevant characters. *cough cough* Skull Kid *cough cough*

The mario series should have 9 fighters now with the recent piranha plant

Where did that Pikmin figure come from? 17.2 million overall even though the best-selling game didn't break 2 million?