Benimaru has a carefree personality, that of an excited and confident man. Even so, he is actually really cautious and cunning as well. He has no interest in serving anyone who he doesn't deem worthy, however, he doesn't belittle those weaker than him either.

He was originally a very hot-headed person but after taking the role of general of the army under Rimuru he becomes more rational and calm in decision making. He is a battle maniac, challenging others who are stronger than him.