Haru is shown to be a bright and cheerful girl of Black Class. As claimed by Tokaku, Haru poses a naive character and trusts anyone without a single thought. She is shown to have a highly optimistic attitude, which is sometimes bothersome for Tokaku since she is not used to friendliness. All in all, Haru's rival classmates appreciate her gullible nature; deeming her as an easy target. She is very forgiving and doesn't mind anyone for bearing any kind of grudge towards her as seen when she still talks in a caring and friendly manner towards every other girl who loses their purpose after chasing her with killing intents.
Like the other women of her clan, Haru possesses the "Queen Bee" power of manipulating others to protect her and let her live the position of highest hierarchy; making others be simply a "worker bee". Haru inhibits and implies this power without being aware of it. Using it unconsciously, she had manipulated Tokaku Azuma to protect her in the black class. Haru had a terrible past, as she was targeted because of her power, and her parents and siblings were killed in front of her eyes while protecting her. Haru's mother had held her while protecting, and her bloody hands slipped off Haru after she died, leaving her alone in nothing but shock and despair as she cried out loud. This incident was probably the reason Haru decided she wanted to live.
As she claims to Isuke on her first assassination attempt, Haru has an immunity to drugs and poisons, and the effect of the laxatives is compartively very mild on her body and mind. Haru also has good fighting skills but tends to use the on their bare minimum, as shown in her fight Otoya Takechi and Sumireko Hanabusa.
In the final episode, it is shown Haru had survived her stab wound from earlier on in the episode because her rib was made of titanium and the edge of the knife stayed from her heart by a small fraction. She is the sole graduate of the Black Class and after the graduation ceremony, she meets up with Tokaku to deliver everyone's diplomas.
