Not much is known about Hidokoro's character.
West Tokyo Tournament
Nagao is introduced in Fantasy during their match against Inashiro Industrial. When their team lost the match in a called game, Narumiya calls out to them saying to go home with their heads held high for their team only lost to the best team in the country for the season.
Hidokoro together with Nagao and Inamoto, watch the finals match between Seidou High and Inashiro Industrial from the stands.
Hidokoro is shown to be in the library with Nagao and Inamoto. He and Inamoto reads an article in a newspaper about Narumiya striking out Seihou High's monster batter, Sano Shuzo at Koshien. Nagao comments that it's not a surprise, thinking of what Narumiya had said to them after their semifinals match.