Adeleine is a friend of Kirby and an artist who is best known for her ability to bring her creations to life.
Much like Paint Roller back from Kirby's Adventure, she can use paintings for combat, most notably in her boss fights. Unlike Paint Roller, she can only be attacked after she runs out from her easel (though she goes down in one hit).
While she's better known for her appearance in Kirby 64, she's implied to make her debut earlier in Kirby's Dream Land 3 under similar circumstances and a different name ("Ado", due to name space constraints). Due to differences in design between the two games, some fans like to distinguish the two appearances despite them being the same character, calling the Dream Land 3 design "Ado" and the 64 design "Adeleine". In some cases, the two designs are drawn as twins.