In Wario Land 4 for GBA, Wario sets out to an ancient pyramid to make a quick buck,not knowing that he’s being accompanied by the ex-princess of the pyramid, Princess Shokora.
The princess is trapped in the form of a black cat for most of the game, but she’s eventually turned back into her true form by Wario. What you might not have noticed is that during each boss stage the black cat runs into an “Items Shop” where she transforms into a Game & Watch-type character who sells Wario items to help defeat the boss. So it’s inferred that this character is actually Shokora, and she’s helping Wario overthrow the baddies in her pyramid.
Throughout the game, Shokora takes the form of ten different characters, giving her a hefty representation in the game’s character list. Upon beating the game, the princess takes one of four different forms depending on how many coins you got during your Wario Land 4 adventure.
Though Princess Shokora had a somewhat substantial role in Wario Land 4, she’s never made another appearance in any game since. I speculate that is because at the end of this game, she is carried off into heaven by a group of angels, making it impossible for her to return to Wario’s world.
Of course, that’s just one interpretation of the ending of a great game.