Blooregard 'Bloo' Q. Kazoo is Mac's imaginary friend. Charming, self-centred, fun and rebellious, Bloo likes to take advantage of the friends at Foster's Home For Imaginary Friends, but he still has a good heart and sometimes apologises for his trouble-making.
Mac is a clever but shy 8-year-old boy who created troublesome Bloo. He spends most of his time at Foster's Home For Imaginary Friends trying to stay out of trouble, but can get easily distracted by sugar - which makes Mac really hyperactive!
Wilt is a tall, friendly and red imaginary friend whose arm is missing and left eye is wonky after an accident in a basketball game. Wilt tries to help out at Foster's Home For Imaginary Friends in any way he can, and he's always happy and positive.
Coco is a mixture between a bird, an aeroplane and a palm tree. She can also only say or write the word 'Coco'. But despite being strange, she comes in handy for her friends at Foster's when she lays her small plastic Easter Eggs - which contain amazing surprises!
Eduardo has big horns, purple fur, long fangs, a spade tail and weighs more than 35 stone! Even though he looks like the scariest of Foster's Imaginary Friends, Eduardo is actually timid and compassionate. He also cries very easily and is scared of almost everything.