BOSS is a character and the first boss in OMORI. He is FOREST PLAYGROUND's local bully who often harasses others for his own amusement. BOSS appears to be a giant purple rhinoceros figure with two green horns on the front of his face, pointing upwards. Compared to the other playground residents, BOSS towers above most of them in size. Known as the FOREST PLAYGROUND's resident bully, BOSS appears to enjoy harassing others for his own amusement. He also is shown to be rather rough towards those he interacts with. Despite his negative traits, he is mostly shown to be a caring individual despite being known as a local bully for the playground residents. [desciption pulled from the OMORI Wiki]

Doesn't necessarily have to be low-pitched. High-pitched and nasally works, too; we're open to different interpretations of this playground bully. 

NOTE: Whoever will be voicing BOSS will also be voicing TUCKER. TUCKER will not need a particularly different voice type than BOSS; just slightly different line delivery. He has a stranger, weirder personality. It is not necessary to audition specifically for TUCKER, just know there is another role attached to this one.