Ryūken
Ishida

Ryūken Ishida is the director of Karakura Hospital, the last head of the Ishida family, and a Quincy who refuses to behave like one. He is Uryū's father, and his son has called him by his first name for years rather than anything warmer.

The estrangement has a cause. Sōken Ishida, Ryūken's father, trained Uryū in the Quincy arts and was killed by Hollows while the Shinigami declined to intervene, and Ryūken read that as confirmation of everything he already believed. He detests the Quincy bloodline on practical grounds, saying it does not let anyone make a living, and put his effort into medicine instead. His wife Kanae Katagiri died some years later, and whatever was left of his warmth went with her.

He is also, when it matters, one of the strongest Quincy alive. He appears out of nowhere to kill two Hollows about to finish his son, does it in one shot each, and scolds Uryū for needing the help. He keeps a Quincy training ground under the hospital, which means he never actually stopped. His refusal is a position he holds deliberately, not an absence of skill, and the distance between those two things is most of what Uryū has spent his life failing to understand.