Renjo Kyu

He is voiced by Megumi Ogata in the anime series and played by Kamiki Ryunosuke in the live-action series.

At first, Kyu doesn't seem to have any family name.

Years ago when he was very young, Kyu met a man named Satoru Renjo and, ever since then, they've become close. Satoru soon became his mentor.

Not long after that, Kyu was kidnapped and held as a hostage by some criminals. Fortunately, Satoru came to the rescue and saved him. Ever since then, Kyu had dreamed to become a detective just like Satoru.

At age 15, he joined Dan Detective School (DDS for short), a prestigious school for detectives owned by the famous Morihiko Dan. Along the way, he befriended several other people who entered the school: Megumi Minami, the girl gifted with the photographic memory, Toyama Kintarou, son of a well-respected police officer with unusually high instinct level and superior strength (having lessons in judo, kendo, and karate), Kazuma Narusawa, a rich computer programmer, and later Ryu Amakusa, a mysterious boy who's very intelligent.

He's enrolled to Class Q (at first, thought to be the lowest class but has a special meaning) along with his new friends.

Later on, it is revealed that Satoru is his real father and a personal assistant of Morihiko Dan though Kyu is unaware of his identity. Unfortunately, Satoru was killed during an operation to take down Meiosei, DDS' nemesis, an event that forced Morihiko Dan in a wheelchair.

Kyu is quite an oddball. He's a bright, sweet and optimistic boy who's very awkward in social situations.

Despite his awkward behavior, he is a gifted detective. More so that he is considered to be Class Q's leader, known for his logical explanations of cases, even more so than Ryu.

His motto is "A Detective must never give up or the case will remain unsolved" which is taught by Morihiko Dan.

He has a good sense of judgment regarding people (when everyone distrusted Ryu, he expressed his open appreciation for him) but often says things that usually infuriate some of his friends around him (resulting of either Megumi or Kinta beating him up). Even though he acts this way, he cares deeply for his friends.

Because of his sweet personality, Ryu slowly opens up to Kyu, which he ends up becoming the latter's best friend. Their friendship eventually puts Ryu in a new path away from Meiosei.

He also cares so much with Megu, which is hinted that she has romantic feelings for him despite his habits often get in the way. Unfortunately, he's oblivious to such feeling.

He and Kinta also have a habit of peeking into Megu's underwear, which results having them both get beaten.

In terms of character and personality, Kyu largely remains the same.

One of the few differences is the introduction. In the manga, he is introduced to the viewers at his school where his principal tells him about his very bad grade. It also introduces his old school and his classmates, which unfortunately we'll not likely to meet in future chapters.

In the anime, the pilot episode shows Kyu in his home watching a detective TV show only to be turned off by his mother, who's slightly irritated by his laziness if it comes to study. When his mother is about to go shopping, Kyu insists doing so claiming he knows what she needs for dinner.