According to her motive to kill Natsumi Kuzuryu, Fuyuhiko's sister, Sato is a very defensive person. She will do anything to protect her friends from being bullied. She sometimes acts like a leader to the rest of her friends and is also shown to be a decisive person. She may have a slightly short temper, as she attempted to hit Natsumi after being mocked by her.

After Sato murders Natsumi in order to protect Mahiru, she turns psychotic and denies it claiming a perverted stalker did it and trying convince everyone (including herself) it was the truth. When she is directly questioned by Hajime, she smiles unnervily and makes more excuses, but becomes distressed and runs away screaming after Hajime tells her that Natsumi had a will to live and hadn't given up after all. This may imply Sato felt guilt for murdering Natsumi after finding out she had hope for the future.