As he dies, he gives his white fedora to Shotaro and asks for Shotaro to become a man worthy of wearing it. It was after the Gaia Tower fell into ruins that Shotaro and Philip, spurred by his advice to continue in his place, learn that Sokichi's body is no where to be found. In Begins Night, Sokichi Narumi and Kamen Rider Skull are among the identities taken by the Dummy Dopant while pretending to be the Death Dopant in a scheme to assume the identities of Futo's upper class members, using Sokichi's form to drive Shotaro off from the case before he realizes the truth. However, Shotaro finally overcomes this and Double ultimately defeats the imposter Kamen Rider Skull. After the case is concluded in Movie War 2010, Tsukasa Kadoya uses a Kamen Rider Skull card he has acquired to summon an iteration of Sokichi Narumi from an alternate dimension, giving Shotaro closure. This Sokichi Narumi does not seem to know Shotaro but recognizes the very thing that the real Sokichi wanted of Shotaro: for Shotaro to become a true detective.
In Kamen Rider W Forever: A to Z/The Gaia Memories of Fate, he gives Shotaro his Lost Driver before fading away as he takes his leave, enabling Shotaro to transform into Kamen Rider Joker. The Skull Memory is one of the 26 T2 Gaia Memories in the film. Koji Kikkawa as Sokichi Narumi/Kamen Rider Skull appeared in the film Kamen Rider × Kamen Rider OOO & W Featuring Skull: Movie War Core in late 2010, with the full story behind Narumi becoming Skull being revealed in the first segment.
By using his Gaia Memory in the Lost Driver belt, Sokichi Narumi is able to transform into Kamen Rider Skull. As Kamen Rider Skull, he still wears his signature white fedora and also wears a white scarf. After the hat is damaged in his fight with the Taboo Dopant, it appears torn, even as a disguise used by the Dummy Dopant. As Kamen Rider Skull, Narumi's strength is increased and he also has access to a unique motorcycle and is armed with the Skull Magnum gun. Before entering a fight, he announces "Now, count your sins!", a motto taken up by his protege. Like any of the Kamen Riders in Double, his weapon is capable of performing a Maximum Drive finishing attack capable of destroying Gaia Memories. Kamen Rider Skull Crystal is the incomplete form of Skull that first appears in the events of Kamen Rider × Kamen Rider OOO & W Featuring Skull: Movie War Core. It differs from Kamen Rider Skull's standard form in that the helmet is iridescent and it lacks the S-shaped "crack". This form is named after the crystal skulls.