He didn't have a choice. Iason, who normally didn't have much in the way of emotions, was totally captivated by Riki. He kidnapped Riki and attempted to train him to become a pet. "Pets" were bred for certain traits- beauty, sexually promiscuity, and a desire to be obedient to their owners.
Riki, being just a normal person and a very rebellious teen, of course didn't have any of these traits and fought it every step of the way. After an escape attempt, and increasing pressure from Jupiter and the other Blondies, Iason let Riki go, but with the secret intention to reclaim him after a year.
Oh okay. Thanks!
Why did Riki become Iason's pet?
I know Iason helped him out and Riki had sex with him to repay him. But why did he become his pet for three years?