An Inherited Feud
Full story regarding his father's and Ban Eiji's feud, although Yuto himself doesn't have all this context
Ban Eiji's teachers knew he was being picked on, but Takashi's gang were much more careful than Ryuu, and they were rarely caught. Eiji latched onto their encouragement that he might be Takashi's boss one day, and in school pursued the same subjects as Takashi in an effort to enter the same field and do just that. No one suspected his motives, because he had a relative who also happened to work in their field- a successful CEO at that. Everyone assumed he was just following in their footsteps, and any classes they shared to that effort was an unfortunate coincidence. Eiji later went as far as to ask that relative to offer Takashi a job. The relative agreed, thinking they were friends at the time, but only had openings in their new Tokyo branch. Eiji had already been promised his position as the CEO's apprentice, under the condition he completed a degree in university. While Takashi worked his way up the company, all Eiji had to do was complete a few more years of school, and the company was practically promised to him.
The CEO was an honorable man, and only offered Takashi the job because he assumed they were friends- why else would Eiji ask after all. He would never have approved of Eiji's long-term revenge and Eiji knew it, so he never let on. After he came back from university the CEO offered to transfer Takashi so they could work together, still under the assumption they were old friends. As much as it pained him, Eiji claimed they'd drifted apart by now and insisted on letting him live his life undisturbed. He didn't want his CEO to find out the truth. Eiji eventually took a wife, had a child, went on with his life otherwise uneventfully for the next several years until the CEO inevitably retired, leaving the company to him.
With full control now, Eiji proceded to move the firm's headquarters, and his family, to the Tokyo branch. With access to all the staff files it wasn't hard to track down Takashi's address and other personal information- he had a family now too! He planned to just confront him at work, but noticed location tracking enabled on Takashi's work laptop over the weekend. He'd taken it to work remotely at a nearby eatery and market not far from Eiji's new neighborhood. Eiji recruited his son to lure him back to their new home- seeing the look on his face finding out in a casual setting would be so much juicier than at work. Meeting Takashi's son around the same age as his own was just icing on the cake.