Haru Mikado is the younger brother of Yuga Mikado and the second son of Gao Mikado and Paruko Nanana. He actively supports his older brother, encouraging Yuga's endeavors without participating in Buddyfights himself. Haru maintains a cheerful and friendly demeanor, frequently expressing admiration for Yuga's activities, especially the Ran-Ga Channel streams. He communicates with honesty and directness, engaging confidently with individuals of all ages.

Physically, Haru is a short-statured boy with distinctive pink hair and an ahoge inherited from his mother. His appearance more visibly resembles his paternal aunt than either parent. He typically wears a multicolored circular-patterned shirt with dark cobalt pants.

Within the household, Haru regularly interacts with family members and Yuga's friend Ranma Kakogawa, who often dines with them due to Ranma's frequently absent parents. Haru's steadfast presence reinforces his role as a supportive family member and an enthusiastic spectator of Yuga's journey.