He then tells Matsu to count his own sins, and the two fight once again. He then goes to fight Matsu, and begins counting his sins: how he didn't see the darkness in Matsu's heart, how he hesitated to fight Matsu when the time came, and because of these sins, Futo suffered. Instead of a Memory Break, Sokichi leaves Komori to die by leaving her trapped under a leaking gas tanker truck, which then explodes. Sokichi transforms into the complete Kamen Rider Skull, and fights the Bat Dopant. Sokichi runs after Matsu but is intercepted by the Gaia Memory Dealer, Eren Komori, who transforms into the Bat Dopant. After infecting not only Sokichi, but most of Futo as well, Matsu departs as Spider Bombs explode all over Futo. He implanted a Spider Bomb in Melissa, and tells Sokichi that the bombs will activate when their host touches the one they love most. Sokichi confronts Matsu and learns his whole reason for becoming the Spider Dopant was because he was madly in love with Melissa, but she loved Sokichi. Sokichi determines that the Spider Dopant's true identity is Matsu, thanks to noticing a quirk in his handwriting appear in a message the Dopant webbed on a wall. After seeing Yaguchi assumed to be the Spider Dopant, he was supplying Museum with test subjects, but killed by one of the Spider Bombs. After receiving a call on the Stag Phone from Akiko, Sokichi gets the motivation to fight off the two Dopants. During the fight, an energy sphere begins emerging from Skull's armor, but its appearance distracts Sokichi and gives the Dopants the upper hand. Shroud notes that Skull is still incomplete, but Sokichi resumes his fight with the Spider Dopant and his horde of Masquerade Dopants nonetheless.
The Driver attaches itself to Sokichi's waist, and he transforms into Skull Crystal against his will. Sokichi is almost killed by the Spider Dopant, but at the last second, Shroud arrives and tosses him the Lostdriver, the Skull Memory already inserted. Sokichi investigates further into Melissa's agent, and at the Yaguchi Talent Office, he encounters the Spider Dopant again, along with the Bat Dopant and many Masquerade Dopants. He rejected the gift outright due to wanting to keep his humanity intact.
Shroud offers him the Skull Memory and Lostdriver when he asked her for suggestions on how to fight the Dopants. After returning home, Sokichi talks to Shroud, who is working on the secret hangar (which then housed the Skullgarry).
A young Shotaro is in the audience, and comments in awe of how cool Sokichi is. However, Sokichi takes the opportunity to attack the Dopant armed with only the Stag Phone. He gives Melissa 100 points, and no one would be killed. After confronting Melissa's agent at the concert, the Man Spider, revealed to actually be the Spider Dopant, attacks the crowd. The letter goes on to say that the Man Spider will rate the song on a scale of 1-100 and for every point below 100, he will kill an audience member. She receives a letter from a man calling himself "the Man Spider" ( クモ男, Kumo Otoko), which tells her to sing a specific song. Sokichi gets a job to protect a friend of his and Matsu's, Melissa, who is a singer. He also provided his childhood friend Fumine Sonozaki (now Shroud) refuge after she was forced to leave her family and she takes up her new identity. While working as a private investigator, he was partnered with a man, similar to his protege Shotaro Hidari's partner Philip, named Seiichiro Matsui (nicknamed Matsu) and had the personal policy of never getting clients in danger.
2.1 Kamen Rider × Kamen Rider W & Decade: Movie War 2010.1.5 The Wind Called B/One Must Chase The Beast.1.4 The S Terror/The Great Detective's Daughter.1.3 The Q on the Radio/Targeted Princess.