"Natsuki appears to be a brash, blunt, cranky, and seemingly arrogant girl at first, with a cute, softer interior as a result of insecurity, convincing Monika enough to class her as the embodiment of a tsundere. While she is impulsive and can speak without thinking, Natsuki truly cares about her friends and, even when she has obvious anger issues, she doesn't enjoy fights or arguments with people. Over the course of the game, it is shown that she worries about Yuri, and, on one occasion, gives the protagonist a note asking him to help Yuri, fearing that if she spoke out then it would cause more arguments. Natsuki is very stubborn and has a hard time expressing how she feels and what she wants. When repeatedly challenged, she often becomes awkward and tongue-tied, then aggressive, and then simply bursts into tears."

-DDLC Wiki