K1-B0 is a polite and serious teenage robot, who has some trouble with human social interaction. Nevertheless, he takes pride in his form and sometimes boasts a little about his wonderfulness and efficient functions, and his aim is to overcome being an ordinary robot. Because of this, he may get offended if he is compared to much more simple machines. While generally well-mannered, he is quickly angered by any prejudice against robots and sometimes threatens to sue people who make "discriminatory remarks". He considers robots a minority group among humans and can get slightly paranoid about "robophobia", supposedly because of past experiences.

Since he is a maturing AI, K1-B0 learns and develops similar to a human.[7] While he has no heart nor brain, he uses his calculations to speak "as if he had a heart". Even still, he often can't read the mood around him and is oblivious to things, sometimes taking things very literally. Due to being overly serious about certain topics and unable to understand sarcasm, he is an easy target for bullying and it's easy to make him heated up, and he is rather easy to read. According to Izuru Kamukura in the bonus mode, K1-B0 has a tendency to rely on others in difficult situations. He feels a bit self-conscious about the fact that he cannot strengthen his body on his own like humans, and he needs help for maintenance and upgrades. Overall, he is also a bit conscious about being unable to do some things humans can, causing him to proclaim that he can do lots of things humans cannot.

Overall, K1-B0 appears to be quite well-meaning and kind. He has mentioned multiple times that he wishes to make people smile and happy. He seems to understand most of human emotions and many of their habits, though some of them only in theory. He can get confused and a bit uncomfortable by his strange classmates, and sometimes reminds them to speak in a way he can understand. He can also get some habits a little wrong, like confusing the action of handholding and handshaking. Like a human, he blushes when he is feeling shy and feels awkward when talking about something inappropriate, though occasionally he may say inappropriate things without realizing it due to his naivety. He can be very expressive with his body language, since as a robot he can move his ahoge and some other parts according to his emotions. Being a robot, he is also very innocent when compared to most teenagers, and some situations make him very nervous and shy.