Philip: "Family, huh. I have something in place of that. They can be a little odd though." Shotaro: [smiling] "You little..."
In The Girl... A, when Phillip looks up how Asuka's father used to say farewell to her, and proceeds to do it for her. D'aww...
Also, it's because he knew that Shotaro wouldn't be able to break the little girl's heart by telling her Double wasn't her father.
In "The F Afterglow", Shotaro rescuing Philip from the burning Gaia Library his fear of losing control to Fang gives him. "The two of us are one Kamen Rider!" Yeah, that pretty much cements it.
In the final part of Movie War 2010, after the final battle, Tsukasa Kadoya gives Shotaro a card before continuing on his journey. It's the Kamen Ride for Skull, which leads to an AR Rider version of Sokichi appearing and complimenting Shotaro, saying "That hat suits you." Cue our three detectives finally making peace with their Sokichi's death.
Along with Kirihiko giving Shotaro the keychain of the character he designed to represent the city they both love. Again, bitter sweet considering what's to come.
Shotaro (voiceover): "I'm going to keep protecting this city. As a Kamen Rider. So watch over me. Okay, Philip?"
Followed up and surpassed by a single line in episode 49.
Raito, this is my Gaia Impact.
The end of Episode 49, when Phillip regains his body and half-boiled tears ensue.
The climax of The Movie. Eternal has won, Double is falling to his death but wait, all the people of Fuuto are chanting "KAMEN RIDER!" in support of their hero, which brings the winds back and allows Double to save the day.
The credits sequence as well. Our quartet watches the fireworks over Fuuto, Akiko breaks the fourth wall informing the audience to wish her luck with Ryu, and then Shotaro and Philip have a good friendship moment as well. All in all, it's a pretty sweet ending.
Shotaro and Philip paying their last respects to the Fallen Hero Katsumi Daido after learning of his tragic background.
Movie Wars Core has Akiko experiencing "Kamen Rider allergies", having grown frustrated with how everyone important in her life is a Rider and how it interrupts everything else, particularly Sokichi becoming a Disappeared Dad. Thanks to the Memory Memory, she learns that Sokichi literally couldn't get near her, thanks to the Spider Dopant's bomb, but that he asked Melissa to be at her wedding in his place. As the wedding starts, Shotaro sits down in the guest seats; Philip asks if he wasn't supposed to be walking Akiko down the aisle, and Shotaro responds "I don't need to". As the doors open and Akiko steps out in her dress, a golden, ghostly image of Sokichi appears and takes her arm, leading her up to the altar.
During the Kamen Rider Drive Chaser V-Cinema, we find out that Ryu and Akiko now have a daughter who Ryu absolutely adores.