A young man who lived in Canada with his mother for eight years before moving to Japan.
- All of the Other Reindeer: Got bullied because of his green eyes.
- Amnesiac Hero: He gets in an accident and forgets about Ren and the time he spent with him.
- Big Brother Instinct: For Ren, Aki and Shima.
- But Not Too Foreign: Haru is of mixed heritage, being three-quarters Japanese and one-quarter American.
- Butt-Monkey: In the first episode, he was attacked by Ren and belittled by his mother.
- Crazy Jealous Guy/Green-Eyed Monster: Over Ren; he beats up Juuzen twice after seeing him on top of Ren (he's trying to see if he has multiple hickeys.)
- Cuteness Proximity: Fawns over Ren.
- Cuteness Overload: Over Ren on occasion.
- Heroes Love Dogs: As a child, he befriended two wolves, both who die four years after he returns to Japan.
- Nice Guy: Emphasized more on the first episode.
- Not Blood Siblings: With Ren and the Kaidou siblings.
- The Protagonist
Haru's adoptive brother.
- Anguished Declaration of Love: He makes one to Haru when he goes back to Canada.
- But Not Too Foreign: After having his past investigated by Mikiko per Haruko's request, it is revealed that Ren is three-quarters American and one-quarter Japanese. It was also recorded that his birth name is either "Ren" or "Allen."
- Dark and Troubled Past: He was abused at the orphanage and barely had any friends. As a result, he finds it difficult to trust anyone.
- Hates Baths: Haru has to literally drag him, kicking and screaming, into the bathroom.
- Heroes Love Dogs: Like Haru, Ren loves spending time with wolves. He also takes a liking to Tanuki, who also gets attached to him.
- Meaningful Name: The character 'rei' in his name means "really small." Ren is 16 and is only 155cm/5'1"
- Not Blood Siblings: With Haru and the Kaidou siblings.
- Older Than They Look: He may not look it, but he's actually a teenager.
- Sugar-and-Ice Personality: Lampshaded by Haru when imagining Ren's ranking hierarchy; Ren generally shows the ice side of his personality, but the sugar side comes out when Haruko is involved.
One of Haru's half brothers.
One of Haru's half brothers.
Haru's biological father.
Haru's adoptive/stepmother mother.
- Deceased Parents Are the Best: From what's shown of her first appearance, she was very doting and cheerful.
- Odd Friendship: She proudly admits that she's friends with Haruko. Their personalities make one wonder how they get along.
- We Hardly Knew Ye: She, along with her husband, die in a car accident, which is responsible for Haru's memory loss.
- Cool Big Sis: She seems like this for her younger sister. This turns out to be a lie.
- Dull Eyes of Unhappiness: One of the big indicators of her true nature.
- Stalker with a Crush: When Haru stops serving her, she becomes desperate to see him that she starts following him.
- Would Hurt a Child: She nearly strangles Ren when she was looking for Haru.
- Yandere: For Haru.