Mac is a smart, creative, somewhat shy eight-year-old boy. He spends most of his time hanging out with Bloo and his new friends at Foster's, where he can avoid his obnoxious bully of a brother, Terrence.

Bloo is Mac's best friend in the whole world, but Mac's mom thinks he's too old for an imaginary friend. Luckily, Bloo has been welcomed into Foster's, where he has a knack for getting into trouble.

With his sharp horns, pointy teeth and monstrous size, Eduardo is one scary dude, except for the fact that he's terrified of anything that moves.

Coco is a little cuckoo. Saying nothing except the word coco, she lays colorful plastic eggs that contain special prizes. Some are good, some are bad, and some are beyond comprehension.

Madame Foster's granddaughter Frankie keeps everything running smoothly at the house. Sometimes an authority figure, sometimes a partner in crime, Frankie is like a big sister to the imaginary friends.

As the matriarch of the home, Madame Foster loves all the imaginary friends, and they all love her for giving them a second chance. She's the ultimate surrograte grandmother: kind, caring and delightfully kooky.

Mr. Herriman was imagined by Madame Foster when she was a little girl. Incredibly proper and strict, this bunny from a bygone era expects nothing but perfection from the staff and residents of Foster's.