Bertha is a strong monster hunter in armor with an axe. She believes all monsters should submit to humans and obey humans, as humans are superior. Often, she will use her magical axe to brainwash monsters into being her dumb obedient slaves and pets. Her magical axe can also turn humans she thinks are unworthy or who insult her into a type of monster girl, such as a slime girl, catgirl, dragongirl, goblin girl, orc girl, or minotaur cow girl. She puts collars on her pets.