Due to his illness, Waku has aged beyond his years. He is only ever seen in his blue hospital pajamas.
Waku's Alzheimer's has caused him to become aggressive, lashing out at hospital staff.
Waku was admitted to the ADDC's a general ward in 2013, and spent two years there. In the weeks prior to his death, he had an altercation with janitor Shinpei Okubo, accusing him of stealing his wallet, then hitting him. On the morning of his death, Waku's body was taken out of the hospital in a laundry cart, then placed into Okubo's truck. It was found by police three months later buried in a remote mountainous location.