Dimensia is a (slightly) crazy jester who made his debut in Kirby and the Distorted Realm, and has since appeared in several fan-made Kirby games.
According to Prima's Strategy Guide, Dimensia is 35 years old. He appears as a white-skinned human wearing what appears to be an assortment of blue and white coloured cloths, with an absurd mixture of polka dots and stripes. His hat is reminiscent of Beam Kirby's Hat, but is blue and green instead of red and orange. Some artworks also depict him with a sword, but this is not usually the case in-game.
In his "True Form" from Kirby and the Distorted Realm, Dimensia takes the appearance of a black orb with white eyes, surrounded by a golden frame with two feathered wings and two smaller, bat-like wings. There is also a feather on his head in this form - exactly the colour of the feather differs from game to game.
Not too much is known about Dimensia's personality, although he seems to have a love for destruction and a mortal hatred for Kirbies, as shown in Kirby and the Distorted Realm.
In his "human form", he is shown to be able to wear various masks to adjust his abilities and let loose bursts of fire, ice and lightning.
In his "true form", Dimensia can copy Kirby's abilities to launch incredibly powerful magic attacks, and also has access to Forsaken, which usually consists of sending a vast number of rainbow-coloured rings in from one or both side(s) of the screen.