Waluigi

Waluigi Wario, more commonly known as simply Waluigi, is Wario's brother. He is the only reason that Wario is alive today. When Wario almost drowned upon falling into the Mushroom Kingdom, Waluigi dragged his unconscious, wet, heavy body back to land and saved him. Waluigi is always willing to help, and always by Wario's side.

The Prophecy
When Morton Koopa Senior (at the time known only as Morton Koopa) first invaded the Mushroom Kingdom and split it into eight worlds, the king of the Mushroom Kingdom at the time sacrificed his life to drive off the Koopa menace. A Yoshi prophecized that the Koopa would get his revenge, and that only a hero from the fourth generation of the Mario family could stop him. The Toads found the Marios (currently in its second generation) and protected them until a time that the fourth generation was born.

Waluigi's Birth
Wanda Wario awoke late one night. She knew that it was time for the baby to come. She had a dream that had told her to go to Subcon, the land of dreams, and see Birdo Elder, one of the last two of the Birdo, a species of pink, egg-spitting dinosaurs. Wanda sailed to Yoshi's Island, and found a tall vine going up to a cloud. She climbed it and met Birdo Elder. Wanda gave birth to two twin boys, Wario, the older, and Waluigi, the younger, before dying. Birdo Elder sent the other Birdo, named Birdo, to take the babies to the Mushroom King, Toadington Toadstool. Along the way, Birdo met up with a green dinosaur named Yoshi, who claimed that he, too, had the fourth generation Mario, two babies named Mario and Luigi. The two agreed to travel together, but looking for the first chance to get ahead of the other. The two fell in love, but both denied it. Eventually, they made it to the edge of Yoshi's Island. Between them and the shore was a tall castle, in which they found the Toddler Bowser, who fought them under the orders of his father, Morton Koopa Sr. When Bowser was defeated, he called his father on his defeaters, and he fought them. Soon, having defeated Morton, the dinosaurs went to the Mushroom King, who sent all four babies, along with his own daughter, Peach, up to the real world to return at the proper time.