One of Mario’s greatest rivals is Wario. He is a selfish and manipulative person. He would do anything to make money and make Mario look ridiculous. His first appearance was in Super Mario Land 2: 6 Golden Coins, as the main villain of the game.
Although he strongly hates Mario, he occasionally works alongside him on the good side, among them is the game Super Mario 64 DS, where the characters are Yoshi, Mario, Luigi and Wario.
Though there is no tangible relationship between Mario and Wario, it is obvious that Wario is in some way ‘anti-Mario’ in addition to turning Mario’s M to Wario’s W.
He seems to have a taste for garlic. He was a hero in the game Wario World, had to cross 4 levels to get the 4 golden signs to open the chest that has his treasure, but before you get it, you have to face purple diamond that has a curse to remove all the treasure because Wario had it locked as a forbidden treasure with the curse. In the end, he triumphs and regains his treasure and the enemy diamond is destroyed. His last appearance was in Super Smash Bros. Brawl as a playable character.
Waluigi was created by the designer Fumihide Aoki of Camelot and appeared for the first time in the year 2000 in the game Mario Tennis of Nintendo 64.
He is the opposite of Luigi, and could be considered as his alter-ego. He has an L, the initial of Luigi, written on his front in reverse order. Waluigi became popular because of his mysterious aspect. From his unexpected appearance, he has continued to appear in later sports games of races, tennis, basketball, football, etc. and he has even been encouraged to participate in the Mario parties since Mario Party 3. However, he has never made an appearance in an adventure game.
We see him committing faults in Mario Golf and Mario Power Tennis both for GameCube, and also in Mario Tennis: Power Tour and Mario Golf: Advance Tour for Game Boy Advance. Although there has been much controversy about the color of Waluigi, since according to the palette of colors used so far, it should be cyan blue. The thing becomes quite clear if one takes into account that Wario uses yellow for the monkey and purple for the letters, being in Waluigi in reverse, the purple in the dress and yellow in the letters.
Overall, Wario & Waluigi are the two important characters from Mario and will continue to be a part of the game in future.