Kobayashi Yutaka, a young boy known to Yuki as Kobayashi-kun, is suspected to have a love interest for Yuki. Whenever we see him in the background, he is looking at her. He first appeared in the crowd of students arriving at school (414 and 419) and again in the background of Yuki sitting in class. He was also in a DPD. His name was finally revealed in Strip 972, and further extended in Strip 1027, when he was recovering from his injuries.
He returned in chapter 7 and received his first speaking lines after Yuki left MegaGamers. He seemed to notice her sitting on a bench. When she got up and fell because of her hurt ankle, he ran towards her calling her name, but stopped when he noticed Ping was already helping her.
Starting with chapter 10, Yutaka became a significant part of Yuki's life, first on the telephone, then sneaking into the Cave of Evil. He found the courage to stand up to Yuki's father, and then was caught up in her close embrace.
His mother Kobayashi Ririka works as a nurse in the hospital that Yutaka was in when he recovered from being hit by a falling Yuki. There are also brothers; one of them is Seiya, though the exact number is unknown.