After getting kicked out of his apartment as his rent was overdue, Shinji moves into ORE temporarily, causing a lot of inconvenience both for himself and the company. After realizing that Ren might have a reason of his own to fight, Shinji is questioned if his resolve is strong enough to take a life, with Ren reminding him of the debt and it would be a shame if he can't pay back in full if dead. Kitaoka/Zolda often tricks him, Shinji was arrested for a murder he did not commit and Kitaoka intended to incriminate him after learning that Shinji is Ryuki. Shinji then mistakes Kitaoka's assistant Goro as Zolda. Kitaoka once tricked him he killed him, making him feel real bad. Later, arrogant mastermind Jun/Gai, took his Drageder Advent card from him after a fight. But with the aid of a kindred spirit, Miyuki/Rai, who also wants to end the war, Shinji regains his card as Jun is briefly taken to jail for his crimes. However the sadistic Asakura/Ohja later kills Jun and then Miyuki. Shinji's offers of friendship eventually wins Ren over, even though they also maintained somewhat of a rivalry afterwards.
When Odin had used Time Vent, only Shinji appeared to notice the time distortion and the difference from current time. He had then went through all his previous endeavors, and while in jail tried to prevent Asakura from escaping (and eventually prevent the deaths of Jun and Tezuka) through Kitaoka who introduced to him as his lawyer like before (which Kitaoka did not fulfill though able to), which he realizes later it couldn't be done when Shiro appeared and said that time in the past could not be altered. At the end of the series, he was stabbed in the back by a Raydragoon before he could transform while protecting a little girl. Mortally wounded, Shinji died with a devastated Ren by his side shortly afterwards following a fight with the Raydragoons. When Shiro Kanzaki reverted time back to normal after Yui died, Shinji's life was restored as a normal journalist with no memory of being a Rider.
In the movie Episode Final, Shinji discovers his mirror doppelgnger Kamen Rider Ryuga, where the latter tricks him into getting absorbed under the assumption that it would save Yui. But Shinji breaks free and defeats Ryuga before he and Knight assume Survive form to defeat the horde of Hydragoons. In the 13 Riders Special , there was another Ryuki, his name was Koichi Sakakibara and when he was mortally wounded, Sakakibara gave Shinji his deck and faded while Shinji became Ryuki. He was lured into the Mirror World by the others under the guise of a truce, but was ambushed. While fighting the other Riders, the Ryuki deck was destroyed by Odin. After Kamen Rider Knight was killed by Verdem, Ren became Kamen Rider Knight. Shinji promised Ren that he will fight and in one ending he takes on the rest of the other riders, and in an alternative ending, he destroys the Mirror World's Power Mirror and has the Rider War reset later.
Blank Form is Ryuki's default form when lacking a Contract Monster, possessing an arm-mounted Ride Visor and weak weapons like the Rider Saber and the Rider Shield. It is much weaker than any of his other forms and any of the other Riders, though it is enough to keep him from disintegrating in the Mirror World. He also reverted back to this form when his Contract Card was stolen by Kamen Rider Gai. As Ryuki, his Final Vent is called the Dragon Rider Kick. Kamen Rider Ryuki Survive is assumed by using the power of Survive Rekka Card given to him by Shiro Kanzaki in episode 34.