Four

Four is the host of BFB and he likes to eat BFB characters and Monsters.

https://vignette.wikia.nocookie.net/battlefordreamisland/images/2/2f/Four_intro.png/revision/latest/scale-to-width-down/350?cb=20180808212016

Four eats Ruby in Chapter 1 Part 3. Four also taught Mimic how to disintigrate when Four ate Mimic.