Umasou is the titular secondary protagonist of You Are Umasou. He is the adoptive son of Heart and thought that his name was Umasou after Heart said he is delicious.
He is a small pink Ankylosaurus with an orange shell and red spikes and tail club.
Umasou is very cheerful and determined to be just as strong as his adoptive father Heart. He's also bold, like how he told Gonza he was well aware of what Heart really is, and did not care.