A couple of stuff about Wario taken mostly from japanese sources
>He likes wrestling and his favorite wrestlers are named Big Bama and Neutron B
>He likes listening to country music while working out
>He has a farming background
>Wario got into Mario Kart by stealing Koopa's kart
>He considers garlic the source of his powers
>Wario's mom is alive and well
>He claims to hate smart things, jerks that are stingy with their money, chocolate with peanuts, marrons glacés, peppers and jigsaw puzzles
>Wario has apparently gone treasure hunting with Mona at least once
>He washes his clothes every 10 days
>Despite considering money the best thing in the universe, Wario claims he'd rather melt his gold and throw it in the river before giving it to Mario
>He cares for his pet chicken Hen so much that he prioritizes her even before his money
>He claims that the reason for his immortality is purely because he doesn't feel like dying
>Wario's status as a human has been called into question as of WarioWare Gold
>His favorite foods beside garlic are stir-fried liver and chives, crepes and rice curry
>According to Charles Martinet, Wario and Waluigi are just "two nice evil guys who found each other", and they bicker like an old married couple.
>He can bench press 200 kg
>Wario once gave 9-Volt a Game Boy Advance SP
>He has a bee allergy which is what results in his Puffy Wario form
>He once ate 100 Poison Mushrooms and developed red and white spots all over his body. He wonders if he would have turned into a Toad had he kept this up.
>Crygor frequently uses Wario as a test subject in his experiments
>He spends quite a bit of the treasure he gains, mostly in food
>He only really gets depressed if he loses money, and even then he forgets about it after a good poop
>Wario likes to have garlic ice cream for dessert
>Wario leaves the door to his house unlocked so his friends can come and go as they please
>Rare once planned for a Donkey Kong x Wario crossover that unfortunately fell through