Link: male, fish monster, over 20000 years old, can breath underwater through his gills and swim really fast with his tail (he can't drown)

Insectosaurus: huge insect like monster, sees Link as her father despite not being related

dr. cockroach: male, scientist with the humanoid body of a cockroach

bob: (male?) indestructible blob

susan: female, human that can grow and shrink her body

there's also the general Monger who is in charge of the base and is supposed to keep the monsters in check