Although Takiishi appears calm, he is an explosive and unpredictable person. He gets bored very quickly, except when he is fighting - this is when he becomes truly excited. He will attack anyone who annoys him, including Endo; however, he finds Umemiya uniquely enjoyable to fight against. Generally speaking, Takiishi does not value people enough to remember them very well, and will only pay attention to someone if that person is bringing him something that he desires or if that person is in his way. Still, Endo and Umemiya both choose to stay close to Takiishi, Endo brings him things that he likes, while Umemiya provides him with the challenge that he needs. At first, Takiishi relied upon Endo for basic help and gradually changes due to his experiences with Umemiya when they fought. He begins to learn his friends' names and to show an interest in humans for the first time. he has an acrobatic fighting style,

While he initially presents as a carefree, laid-back, and warm individual, he is secretly a dangerous, deeply obsessive, and violent delinquent who worships his partner, Chika Takiishi, as a god. He apparently is in love with him, and doesn't mind being smacked around by Chika, and won't even fight back, He often buys takiishi things he wants or seems to like, Endo possesses immense physical strength, capable of knocking down opponents with just a few well-placed, brutal blows. His punches carry enough impact to leave enemies with zero time to react. Endo acts as a literal shield and punching bag for his partner, Chika Takiishi, frequently taking Takiishi's iconic "Backhand Slaps" without flinching.