Most popular answers: Pokemon Trainer, Ice Climbers, Olimar, Game and Watch.
All of those characters share a common trait(s) that makes them common. In comparison to Luigi.
Last time I checked, this board is god-awful at getting people that come up with original ideas or think for themselves. "Hey guys, lets just say ICs since tharrs two people lawl. Or pt cuz thers 3 diffrent pokemons rofl. or olimar cuz he has other people do his work hahha."
Analyze their movesets for all their worth. Think about what makes a character unique, what really sepeartes them from the cast in a way that no others do. The same can apply for all characters above, but moreso for Luigi than anyone else. Alright, let's take a look at what we have on the table.
He looks pretty similar to Mario. So you might think "oh but straked, there moves are practically teh same. you r wrong."
Well... no. Luigi does not follow the same mechanics other smashers do. To start, his most noticeable attribute is his traction, fall speed, and aerial movement. He is the only character in the game that has this feature. It can be good in some cases, bad in most. Luigi cannot shieldgrab or punish laggy moves because he gets knocked back far. This eliminates his strange ways of killing, and doesn't even set up for shieldgrabs. Luigi can't do anything. He is, however, immune to gamechanging things like Diddy Kong's banana combsz, or jab locks. Now, let's take a look at his moveset. He has some things that are completely unique in the regard that no other smasher has something like this.
When saying someone like Olimar or Ice Climbers are unique because they rely on others, they aren't unique. There's a select few characters that have these similar qualities. Olimar needing pikmin to fight can be compared to Nana. Without the partner, you'd be fighting an uphill battle with a character doomed to be bottom tier
trash. You also might say Pokemon Trainer is unique for having 3 different characters you play as. I'll give you that once since it's entirely it's own, like being able to use Nana and Popo at once. But it follows the same rule that "you're using more than one character in a single game." They're similar in the sense that you have to use an extra no matter what.
Moving onto his moveset, play as him one game, and tell me you aren't surprised. His recovery is extremely strange. Keep this in mind. All Fire Jump Punches are Super Jump Punches, but not all Super Jump Punches are Fire Jump Punches. It's hard to understand if you haven't already done it. Now, the move itself is very odd. If used up close, you'll imitate the sound of a bat cracking, fire will shoot up, and they'll be sent spiraling upwards. If you don't connect properly, it'll do anywhere from 0.1 - 1% damage. Misfire. 1/8 chance of shooting a considerable distance with absolutely amazing damage and knockback. Nothing in the game is like it. And Judgment is much different, though I'd love to believe they have similar properties.
Every move where you have to input "down" on the control stick sends them... well... down. They're all meteors, and it's obvious they don't work in traditional ways. His Dtilt has some odd properties. At higher percents on stage, it pops them right off the ground in a silly animation. When used offstage of a platform, it's a weak semi-spike. His Dair is a quick attack that's more than meets the eye. If you land it on a specific point on his body, it'll send them straight down. Good meteor that nobody can truly master, though that's up for debate. Even his Down
Taunt can do this. Snake is the only other character in the game with a damaging taunt, and Luigi has the good one. It's fast, kicks them straight down, but still techable. You'll never land it, but **** if it isn't rare.
Luigi's Nair. Quite possibly the best sex-kick in the game, it's very high priority and hella fast. It sends your opponent toward the sky. Straight up. No other move has this odd knockback property, and it's extremely good for the man in green. And his dash attack. Pause during his dash attack. That's all that really needs to be said.
As for smashes, his do some pretty strange things in terms of where they go and how the get there. Fsmash can be angled to kill earlier or lower, and the other two are fairly standard.
His Ftilt angled down has absolutely
no knockback. It is the only move in the game that does this. (nittpickers, have at it.)
Aside from that, he's the only character to have 1% high trip ratio that everyone else.
He's just different.
- 3 seperate Pokemon with average movesets you'd expect.
- Relies on pikmin that are plucked at random. SA frames at kind of unique.
- Two fighters at once.
All 4 can be considered unique. It's in the eye of the beholder, if you think someone other than Luigi is weird (you probably will), then far be it from me to tell you you are wrong.
EDIT: You are wrong.
There's probably 30-odd characters that are unique.
