Oreki is a high-schooler with messy brown hair and green eyes. Due to his very lazy lifestyle, he almost always has a tired or bored look on his face. His hair is especially very messy when he wakes up. He is shown to be a quiet student, and never concerned about things that happen around him. Despite being shown as an average high school student, he is quite intelligent and perceptive. The reason for his usual laziness is because he wishes to "save energy." Even though he is shown to be quite lazy, he never leaves his homework undone, as pointed out by Satoshi. He's considered lazy and apathetic, always living on the "gray" side, and is not interested in any activities that might waste his time and energy. He actually never intended to join any club, but his sister ordered him to join the Classics Club to save it from being disbanded. Even though he might not seem it, he's unbelievably good at solving mysteries and seems to be able to always find a solution if he gives it a thought. He has a habit of holding his bangs whenever he's thinking about a mystery.

Senkuu is a straight-forward, confident, and highly logical individual who can come off as arrogant. Even so, his borderline-overconfidence does not cloud his judgment, as he is often backed up by his superior and vast knowledge of science. Senkuu never belittles those who are less knowledgeable than him. Rather, he encourages and inspires everyone around him to do better. Because of his charisma and caring nature, people tend to gather around him, both allies and supporters alike. However, he can act over-the-top at times when he is excited over a creation or at the discovery of something new. (Source: Dr. Stone Wiki)