The stories protagonist. Born in Boston and grew up in Saitama prefecture. A high school student who enjoys baseball more than textbooks.He was 'named' by Conrad when he mentioned to Yuri's mother how, where he comes from, Yuri means July. Early in the show, bullies make fun of Yuri's name by calling him "Shibuya Yūri, Harajuku Fūri" (advantage Shibuya, disadvantage Harajuku) � a reference to popular districts of Tokyo. In the English dub, this becomes a pun on "Yuri is short for urine."

When Yuri arrives in Shin Makoku, he is declared the 27th Maoh of the Mazoku ("Demon Race"). Yuri easily gets caught up in his emotions to the point of loosing control of himself. He is a little bit quick to anger, and once he's on a rampage he can't even stop himself. A music teacher he once had dubbed his rants "the Turkish march". When he is angry or sad or has a strong emotion his natural powers emerge. Yuri uses expressions from historical dramas when he gets this way, which probably has to do with the fact that he loves historical dramas. They call this condition is sometimes called Maou mode (「上様モード� (uesama mo-do)(emperor mode) in Japanese). In the anime this form can be recognized mainly by the longer hair and demon eyes. He can summon powerful magic (majutsu), even in the human territories (a notable feat as most Mazoku cannot perform magic outside their country). Yuri's magic is manifested in various shapes - usually one or more great water dragons, or some messy magical "creature" made from mud, food morsels etc. After spending time in this form, Yuri becomes worn out and in some cases passes out and doesn't remember what happened afterwards. Later, Yuri learns to control his power and uses it to close the first of the Forbidden Boxes. In the beginning of season 1, he often fainted after he used Maryokou (especially in Human land) due to exhaustion. But later on he was able to maintain his consciousness after returning to his "former self".

His given name is Conrart; Yuri nicknames him "Conrad," which is "closer to English" and easier to pronounce with a Japanese tongue. Conrad is the second child of the previous Maoh, Cecilie von Spitzweig. His father was human (also considered the greatest swordsman in the Demon Kingdom; Dan Hiri Weller). His ancestor, Lawrence Weller, fought alongside the Original King during the war against Soushu.On his 16th birthday, he decided to live as a Mazoku instead of a human. He fought on the front lines for the Mazoku during a war against the humans. He and Yozak are the only two survivours of the Battle of Lütenburg. He was also put in charge of the soul at the request of Suzanna Julia von Wincott, that was to be the new Maoh, and brought it safely to Earth so that it could be born.

Furthermore, he was the one who was the inspiration for Yuri's name. He stated that "Where I come from, the month of July is called Yuri", which made Yuri's mother name him Yuri because he was born in July. For this reason, Yuri dubs him 'Nazukeoya', which is a person who names someone (Conrad is also known as Yuri's Godfather by his mother). Cecilie named the blue flowers she grew "Conrad Stands Upon Earth".

When Yuri first came to Shin Makoku, Conrad was the one to find him (after some humans and Adelbert) and bring him safely to the castle. He acts as Yuri's bodyguard and vows to protect Yuri with his life. He was described by Yuri as almost perfect with fine looks and a mild demeanor but he makes the worst jokes.

Conrad is a swordsman ("the best swordsman in Shin Makoku" - according to Wolfram) who looks after Yuri. Conrad possesses no maryoku (demonic magic) due to his mixed heritage of human and mazoku. Eventually it is discovered that Conrad's left arm is one of the keys to the 4 magical boxes ('The End of the Wind') that have the power to destroy the world. His ancestor, Lawrence Weller, fought along the Original King. As Conrad's father was not a Mazoku noble, he doesn't have "von" in his name.

After he loses this arm in a battle, he disappears after swearing to Yuri that he'll never die and leave him alone. Later, he reappears with a new arm, and seems to have betrayed Shin Makoku by joining their human enemies, Big Cimaron, who were after the four boxes. However, it is learned that Conrad only betrayed them to learn about the whereabouts of the boxes. His plan was, when the four boxes were gathered, to steal them and return to Shin Makoku. He went as far as pushing Jozak off the edge of the cliff to show his alliance to Big Cimaron. When King Belal orders Conrad to execute Yuri, Conrad instead frees them, and protects Yuri from arrows.

A young man who finds himself engaged to Yuri after a mistake. He is a 'bish�nen', which means a pretty or beautiful boy. Wolfram possesses fire magic, as well as being adept with a sword. He is the half-brother of Conrad and Gwendal. He has extremely high pride and is hot-headed. He is arrogant and short-tempered but can also be quite compassionate at times. He is called "little lord brat" but he is really very manly and reliable (according to the author he is the most many out of the three brothers). He is the only one of the previous queens three sons who inherited her emerald green eyes and blonde hair. It seems he also inherited fire magic from her side of the family but his selfishness from his fathers side. Wolfram is obsessed with Yuri and insists on following him everywhere as he claims it is his duty to protect his fiancé though he also seems to want to prevent him from cheating on him. His ancestor, Rufus Bielefeld, fought alongside the Original King(the great one).

Near the end, there is a time when Wolfram is possessed by Original King, who in turned was possessed by Soushu. The key he possesses, his heart, is ripped out by Original King in order to open one of the four boxes, 'Hellfire in Frozen Land' ('Hellfire on Frozen Tundra' in Japanese translation). Because of this, Wolfram temporarily dies, but is revived when the Original King returns the keys to their owners.

The eldest son of Cecilie. From the beginning, Gwendal has objections to Yuri becoming the Maoh. He is a skilled tactician and is capable of using earth magic and can cast barriers.When not otherwise busy, Gwendal indulges in his hobby of knitting and sewing but often his creatures look nothing like what they're supposed to (for example a bear got mistaken for a black pig or a cat that looks like a raccoon). He is adamnant that knitting helps him sharpen his concentration but actually its a stress reliever for him since childhood. He is also quite fond of cute animals or cute objects such as the dolphin keychain (Bandou-kun) Yuri received at the dolphin show and later gave to him. His childhood best friend is Anissina von Karbelnikoff, an inventor who often tests out her inventions on him, much to his displeasure. Anissina is also the one who taught Gwendal how to knit.Gwendal's left eye is a key to one of the four Forbidden Boxes, the "End of the Earth".

Gwendal is a tough guy except when it comes to his childhood friend, Anissina, and his brothers. He is afraid of Anissina and often hides from her so he can prevent being used in one of her crazy experiments. He is even seen sweating in panic at the thought of her. While he does not outwardly show much affection towards his brothers, he shows in times of great stress that he does care, an example being his decision to stand against the Original King to save his little brother, Wolfram. Jozak, who was sent to locate one of the Four Forbidden Boxes, tells Conrad that Gwendal really cares for Conrad's wellbeing and doesn't want Conrad to worry despite the Original King's wishes for Conrad to find the Boxes. His ancestor, Siegbert Voltaire, fought along the Original King.

Ken met Yuri in middle school, where they were in the same class. Despite going on to different high schools, Ken still serves as the manager of Yuri's baseball team, and the two get together on a regular basis. Ken is known to smile often and keep relatively quiet. He later finds himself involved with Yuri and the other world when it is discovered he houses the soul and memories of the Great Sage. Dr. Rodriguez was responsible for handling his soul, around the same time when Conrad transported Julia's soul.

Ken is very smart and calculating, and capable of defending himself. He was the Great Sage in his past life - the right hand man, tactician and strategist to the Shinou, the Original King of Shin Makoku. He still remembers things from that life and other lives that he has had. He is a good friend and ally to Yuri and helps him a lot throughout the series, though it often seems he's working on his own agenda. He even constantly repeats to the Original King that he "likes Shibuya", and won't let anything bad happen to him.