Sokichi Narumi

Sokichi Narumi (played by Koji Kikkawa) was Shotaro's mentor (whom he refers to as "boss"), Akiko's father, and founder of the Narumi Detective Agency.

Background
Prior to founding his agency Sokichi worked for the Sonozaki Family, and was even given the Lost Driver as a reward for assisting them in their schemes. He founded the Narumi Detective Agency to redeem himself for his part in their schemes. His idealogy was to put his client's safety above everything else. One day he took Shotaro Hidari under his wing. During the events of "Begins Night," he and Shotaro make a rescue attempt to get Phillip away from the Sonozaki family. Unfortunately he is shot and tells Shotaro to continue in his place and look after his daughter as he dies.

Movie Wars 2010
The Dummy Dopant assumed Sokichi's guise as well as others that were supposedly brought back by the Death Dopant. Near the end of the crossover part of the movie, a Sokichi Narumi from an alternate dimension appears (the true Sokichi Narumi) appears and thanks Shotaro for doing as he promised.

Kamen Rider Skull
With the use of the Lost Driver and the Skull Memory, Sokichi transforms into Kamen Rider Skull. Skull is unique in that besides wearing a white tathered scarf he also wears a white fedora. Like Skull Rider, Skull appears to be a homeage to Skull Man, who was adapted for the creation of Kamen Rider 1.

Lost Driver
The Lost Driver is Skull's transformation belt. Sokichi received this as a reward during his employment for the Sonozaki Family. It is similar in design to the Double Driver used by Double but has one Memory Slot instead of two.

Skull Memory
The Skull Memory is the Gaia Memory used for the transformation into Kamen Rider Skull.

Skull Magnum
The Skull Magnum is a firearm similar to the Trigger Magnum used by Double. It is gained through the power of the Skull Memory.

Motorcycle
Skull also has a modified Honda CBR1000RR motorcycle similar to Double but is all black in color.