Chiaki normally has a quiet and sleepy disposition, but she becomes a lot
more lively when discussing games and concentrates hard when playing. She
has a number of unusual habits, such as dozing off while playing games and
taking long pauses during her conversations to think about everything she
wants to say. She sometimes even sleeps while standing and forgets to
breathe when she's playing games. She also quite often uses gaming terms
and references.
Chiaki is very calm and she once mentioned that she has never screamed.
She often helps Hajime Hinata during the Class Trials and provides
important points. She can be stern and bluntly honest, even at times
forgetting to take other people's feelings into consideration.
While Chiaki is extremely observant and analytical, she lacks knowledge on
a variety of ordinary subjects due to the nature of her existence. For
example, she doesn't know where milk comes from (she mentions that she
knows how babies are made, though). She doesn't really understand how
romance or love works, is very curious about it. She also feels a bit
uncomfortable around animals, because they're unpredictable and feel warm
when touched, which is "a bit scary" in her opinion. She is occasionally a
bit playful and tries to make jokes or play little pranks on Hajime,
though they're a bit weird and sometimes borderline creepy.
Chiaki usually ends her sentences with a negative note even though she
actually means to compliment someone or cheering someone, such as "...I
think", or "Maybe...". Hajime once said that sometimes he wishes that
Chiaki would end her positive sentence on a positive note. However, she
truly does care about and wants to protect everyone. She dislikes killing
more than anything and she gets very serious about the topic. She is the
nicest towards Monomi and she is very understanding towards Nagito
Komaeda, even though his actions frustrate her.
While she is based on some of human Chiaki's traits, AI Chiaki differs
from her in some ways. Unlike the human, she appears constantly sleepy and
her way of speaking is much less natural sounding. As an AI she also
appears unusually calm and unfazed, even during her own execution, which
is very different from the human Chiaki's much more human and painful
reaction. She also has her own identity as an AI created by Chihiro,
considering him her "dad" and Alter Ego and Usami her siblings. Some of
Chiaki's behavior also appears a bit childlike, most notably her
handwriting and drawings that resemble ones of a young child, which could
be a result of her being a relatively young AI. However, she matures
throughout the course of the game and in the end, she even seems to be
able to resist her programming, albeit just a little bit.