Allen Holmes

Sokichi Narumi Kamen Rider Skull, he is also Simon's father (whom he refers to as "boss"), and founder of the Holmes Detective Agency in Futo City.

History
While working as a private investigator, he was partnered with a man, similar to his protege Simon Holmes's partner Charlie, named Seiichiro Matsui (nicknamed Matsu) and had the personal policy of never getting clients in danger. He also provided his childhood friend Shroud refuge after she was forced to leave her family and take up her new identity. Allen gets a job to protect a friend of his and Matsu's, Melissa, who is a singer. She receives a letter from a man calling himself Spider Man, which tells her to sing a specific song. The letter goes on to say that the Spider Man will rate the song on a scale of 1-100 and for every point below 100, he will kill an audience member. After confronting Melissa's agent at the concert, the Spider Man, revealed to actually be the Spider Dopant, attacks the crowd. He gives Melissa 100 points, and no one would be killed. However, Allen takes the opportunity to attack the Dopant armed with only the Stag Phone. A young Simon is in the audience, and comments in awe of how cool Allen is. After returning home, Allen talks to Shroud, who is working on the secret hangar (which then housed the SkullGarry). Shroud offers him the Skull Memory and Lost Driver when he asked her for suggestions on how to fight the Dopants. He rejected the gift outright due to wanting to keep his humanity intact.

Allen investigates further into Melissa's agent, and at the Yaguchi Talent Agency encounters the Spider Dopant again, along with the Bat Dopant and many Masquerade Dopants. Allen is almost killed by the Spider Dopant, but at the last second, Shroud arrives and tosses him the Lost Driver, the Skull Memory already inserted. The Driver attaches itself to Allen's waist, and he transforms into Skull Crystal against his will. Shroud notes that Skull is still incomplete, but Allen resumes his fight with the Spider Dopant and his horde of Masquerade Dopants nonetheless. During the fight, an energy sphere begins emerging from Skull's armor, but its appearance distracts Allen and gives the Dopants the upper hand. After receiving a call on the Stag Phone from Gwen, Allen gets the motivation to fight off the two Dopants. After seeing Yaguchi assumed to be the Spider Dopant, he was supplying Museum with test subjects, but killed by one of the Spider Bombs. Allen 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. Allen confronts Matsu and learns his whole reason for becoming the Spider Dopant was because he was madly in love with Melissa, but she loved Allen. He implanted a Spider Bomb in Melissa, and tells Allen that the bombs activate when their host touches the one they love most. After infecting not only Alllen, but most of Fuuto as well, Matsu departs as Spider Bombs explode all over Fuuto.

Personality and Abilities
A hard boiled person who helped the citizens of Futo as both a detective and as Skull, Allen lived and died while helping others. At a younger age, Allen was already a rather cheerful man with his partner Matsu while sometimes showing a comical and stubborn side. As well as helping Shroud through sheltering her, Allen still called Matsu his partner despite his betrayal and crimes later on. It seems the confrontation and death of Matsu combined with no longer being able to meet Gwen again has changed Allen though, as he seemingly became less cheerful and more cold.

Although he seemingly wasn't with Gwen much in her childhood, Allen clearly cared for her which was shown when he became motivated through talking with her on the phone. This fatherly side is also shown through his mentoring of Simon whom he acted both strictly and understandingly. He is quite forgiving towards others as he forgave not only Matsu, but Allen as well when he indirectly caused his own death. He was also the one who convinced Charlie to make his own decisions right before his (Allen) death.