Ryuuken has one son, Uryuu. Introduced to the series long before his father, Uryuu is a passionate believer in the Quincy. He claims to hate Shinigami for failing to save his teacher, Souken, from being killed by a Hollow. His duty, Uryuu feels, is to regain the honor of the Quincy by proving their strength to the Shinigami. To do so, he challenges Kurosaki Ichigo – a human who doubles as a Shinigami by freak accident – to a Hollow hunting contest. Instead of besting Ichigo, the two end up working together to fight off a Menos Grande.

Since this incident, Uryuu has found himself in a difficult position regarding the Shinigami: on the one hand, he continues to tell himself that he hates all Shinigami across the board. On the other, Ichigo & Co. are probably the first real friends that Uryuu has ever had. Thus, although he continues to say out loud that he and Ichigo are enemies, when Ryuuken makes his bargain to give Uryuu his powers back, that he must never associate with Shinigami again, Uryuu has to think long and hard about it first. In the end, he finds a loophole: since Ichigo is a substitute Shinigami, not a "real" Shinigami, there is nothing wrong with Uryuu getting involved in his affairs. Still, when it comes to Shinigami, Uryuu remains coy.

Ryuuken and Uryuu have a dismal relationship. Ryuuken never approved of Uryuu's Quincy training and repeatedly ordered him to stay away from Souken. He calls Uryuu talentless, cowardly, and pathetic, and always fixes him with a condescending look. As a child, Uryuu wanted to become strong to show his father the worth of being a Quincy – but the two of them were never close. He never understood his father's sense of justice; to him, it seemed that all Ryuuken cared about was money. If Ryuuken believes that one should focus on protecting the living instead of saving the dead, why does he hate the Quincy? Isn’t that precisely what the Quincy do? The years have gone by, and Uryuu still doesn't understand his father's position.

As for Ryuuken's feelings for Uryuu, he still seems to think of his son as something less than shoe scum. "...Whether he chooses to let the powers grow or die is his choice," Ryuuken says after helping Uryuu get his powers back, "Him living or dying is his choice as well" (Chapter 241). However, a revealing conversation between Souken and Uryuu in Chapter 214 suggests that Ryuuken is not entirely indifferent to Uryuu after all. He isn't interested in the Quincy because he has a family to provide for, Souken says. At the same time, Ryuuken's sense of justice is different from Uryuu's because the person he wants to protect is different. Souken's implication is that Ryuuken's "person" is Uryuu. If that is in fact the truth, then Ryuuken's cold behavior could be a charade to dissuade Uryuu from further training and therefore keep him out of harm. That last bit a theory, however; more will undoubtedly be revealed as the series moves on.