His daughter who he loves and cares for so much, he was especially proud of her when she became an Angel as well as Michael's Ace, but somewhat conflicted as he was also a bit sad that he couldn't have grandchildren, that is until a solution was found that allowed her to mate without falling. Aware of Irina's feelings for Issei, he constantly encourages the two to have children, an act that constantly embarrasses Irina.
Issei and his family were Touji's neighbors before he moved. Touji appears to have a good relationship with Issei, as he would often come over and play with his daughter Irina. Issei also views Touji as an uncle. They meet again years later in Volume 18, Touji has great trust in Issei, entrusting his daughter into his care and often encouraging them to have kids, so he can have grandchildren.