His "salty" personality is established as he mocks the concept of "effort" in sports, serving as a foil to Hinata's pure enthusiasm.
The duo’s practice is interrupted by the other two new first-year applicants: the tall and cynical Kei Tsukishima and his friend Tadashi Yamaguchi . Tsukishima immediately antagonizes Kageyama by bringing up his "King of the Court" nickname and the teammates who abandoned him in middle school. Haikyuu!! Episode 3
Denied entry to the gym by Captain Daichi Sawamura until they can cooperate, Hinata and Kageyama practice outside. Sugawara, the team’s vice-captain and setter, begins helping Hinata with his receives. His "salty" personality is established as he mocks
He reveals he is the official setter but encourages Hinata to view Kageyama as a "formidable ally" rather than just a rival. Denied entry to the gym by Captain Daichi
In the manga , the duo is shown practicing for several days before Kageyama trusts Hinata. The anime streamlines this, having the breakthrough occur shortly after the confrontation with Tsukishima. Haikyuu!! Episode 3 - Meeping Anime
Kageyama remains cold, telling Hinata he will only toss to players he deems "essential to winning"—a status he believes Hinata has not yet earned.