Simon Holmes

Simon Holmes is the left hand side of Kamen Rider Double Detective, but also a Rider in his own right as Kamen Rider Joker. A self-proclaimed "hardboiled detective", he dresses in a retro fashion based on late-1930s style, favoring fedora hats and waistcoats. He is often called 'half-boiled' by his friends, however, because he cannot fully shut out his doubts, often acts according to his feelings, and has difficulties making cruel yet necessary decisions, contrary to his hard-boiled aspirations. He works as a private detective in the Windy City and as chief of the Windy City Detective Agency. Eventually, he becomes the legal guardian of Marie Sandoval, the late governor's young daughter.

History
Vowing to stop anyone that makes his city cry after, as a child, witnessing Sherlo Ishino's first fight with the Spider Drivor, Simon eventually became Sherlo's protégé. His final job with Sherlo involved investigating a mysterious organization, at the behest of an equally mysterious client. While infiltrating a Gaia Drive research building, Sam met Charlie for the first time. However, due to Simon's recklessness, their cover was blown and it indirectly led to Sherlo being shot to death. Sherlo then left Sam to continue on in his stead, giving Simon his prized fedora and making him chief of the Windy City Detective Agency in his final moments. Shortly afterwards, Charlie and Simon used the Double Driver - which Sherlo had been carrying, perhaps with the intent that he become the body of Kamen Rider Double Detective - to transform for the first time, in order to escape.

Refusing to let his mentor's memory be in vain, and to atone for his mistake, Simon works to stop the Drivor crime wave by being the man on the street, contacting his various informants and transforming into Kamen Rider Double Detective by providing his body for the combination.

Simon's physiology is not ideal for Gaia Drive use, and he was never Shroud's ideal choice for the 'body' half of Kamen Rider Double Detective. Because of this, he had trouble maintaining their Rider form when Charlie's power was evolving. However, he later proves that he has a knack for being the 'wild card', being incredibly difficult to predict in such a manner - this quality leads not only to him resonating strongly with the Joker Drive and match Charlie's heightened power, but also displaying the ability to exceed expectations and being able to transform into Kamen Rider Double Detective Xtreme by sheer willpower.

Sam also appears to be the one who came up with the names of Kamen Rider Double Detective's finishers, as demonstrated in episode 16 when he decided to call FangJoker's Maximum Drive "Fang Strike". Though this is ostensibly to enable him and Philip to synchronize themselves better, it seems Sam simply likes doing it, as he names his attacks when he fights solo as well.

Personality
Simon's basic personality is an homage to the fictional detective Charlie Marlowe (ironically, his partner's namesake), as is his aspiration to be a hard-boiled detective. Sam's decisiveness and honed detective intuition make him a remarkable detective even without the help of his partner. However, his friends and contacts often refer to him as 'half-boiled', as he wears his heart on his sleeve and let his emotions get in the way of making the cruel yet necessary decisions that real hard-boiled detectives, such as his mentor, would have little problem making. Even though his emotion and dedication to the choices that he makes causes him to come to blows with his partner and others, there is an affection to their calling him 'half-boiled', and eventually he accepts it as his way of doing things. Despite his flighty exterior Sam cares deeply about his clients, his friends, and his city and will do anything in his power to protect them.

Abilities
Being trained by Sherlo for years, he has honed his detective skills enough to become a competent private detective who is able to solve cases even without the help of Philip. He has a keen eye for details and has good deductive intuition, as such he is able to piece information together quickly and coherently and thus rarely fails in determining the culprit behind cases. His skills is such that the police, specifically Drake, would often come looking for his help when dealing with Drivor cases.

Oddly enough, he has also shown a great skill in locating pets easily, more so than finding people, first seen when trying to locate a cat not knowing it was a trick and finding Mick. As a result, he has developed a fame out of it and most of his clients sought him out so to locate their lost pets, to his chagrin.

In combat, Simon proves himself to be a competent fighter even without using Gaia Drives, being able to take on several Masqueraders without having to transform. Even in a weakened state of becoming an old man due to the Old Drivor, he is still able to make use of whatever motor skills and stamina left in his deteriorated body to put up a good fight.

Gaia Drives
The Gaia Drives are mysterious USB flash drives imbued with the powers of the Earth itself. Originally created by Shroud after leaving the Carroway Family's Museum organization, these Gaia Drives end up in the possession of Simon and Charlie, and can only be used through the Double Driver or a Lost Driver. Two can be inserted into the Duo Driver, allowing Simon and Charlie to transform into Double Detective. Simon's left-half Drives, called Body Drives, determine the type of attack or weaponry that Double Detective uses.


 * Joker Drive: The Joker Drive, also known as the Trump Card Drive, allows the user to increase fighting potential, becoming the Skill Warrior. When used, half of Double Detective becomes the black Trumping Left Half. When the Joker Drive is placed in the Maximum Slot on the Double Driver, it allows Double Detective to execute the Joker Strike Rider Kick. Simon can also use the T2 version of the Joker Drive with a Lost Driver to become Kamen Rider Joker. Later, after T2 Joker Drive was destroyed and after Charlie disappears, Simon would use the original Joker Drive to transform into Kamen Rider Joker.


 * Metal Drive: The Metal Drive, also known as the Steel Drive or the Fighter Drive, empowers the user with great strength, becoming the Superpowered Warrior. When used, half of Duo Rider becomes the silver Fighting Left Half.


 * Trigger Drive: The Trigger Drive, also known as the Sniper Drive, turns the user into an expert marksman, becoming the Magnum Warrior. When used, half of Duo Rider becomes the blue Sniping Left Half.

Kamen Rider Joker
Ability Perimeters: Through the power of the T2 Joker Drive and the Lost Driver, Simon uses the power of the Joker Drive to its full potential. When the Drive is placed into the Maximum Slot, Joker executes either a Rider Punch or Rider Kick Maximum Drive. Along with Kamen Rider Cyclone, the two can execute Double Rider Kick Maximum Drive. This form is lost after the T2 Joker Drive is taken by NEVER; But, after Philip dissolves into data and becomes one with the Earth, Simon finds in the present Charlie gave to him, the Lost Driver from the incident. He uses his original Joker Drive in place of the T2 Joker Drive to become Kamen Rider Joker again. However, one year later, Simon is overwhelmed by the newly formed EXE group until Charlie returns. It is shown that if he finds Charlie is in the middle of one of his obsessions again and too occupied to fight, he will swap out the Doubke Driver for the Lost Driver.
 * Height: 195 cm.
 * Weight: 85 kg.
 * Punching Power: 1.25 tons
 * Kicking Power: 3 tons
 * Maximum Jump Height: 30 m
 * Maximum Running Speed: 100 m. per 6.2 sec

Lost Driver
With Sam unable to use the Double Driver he uses a Lost Driver he received from Skull instead to transform. This Memory Driver was lost in the battle with Kamen Rider Eternal, but Shroud gave Charlie another Lost Driver and Charlie kept it, which he later gives to Simon. To transform, Simon places the Joker Drive in the Memory Slot to transform into Kamen Rider Joker.

Gaia Drives

 * T2 Joker Drive: The T2 Joker Drive was one of the 26 T2 Gaia Drives and the first Gaia Drive used by Kamen Rider Joker, both for the transformation and Finisher. The T2 Joker Drive was the Sole memory that NEVER was unable to locate during their reign over Windy City. However, after being visited by Kamen Rider Skull, Sam realizes that the Drive was what created the recent hole in the Agency's ceiling, having been called to him as he was the person that resonated most strongly with it. He then takes the Drive and uses it in unison with the Lost Driver that Skull gave him to combat the T2 Drivors and rescue Charlie. However, the T2 Joker Drive was lost when Eternal was able to defeat Joker using the T2 Unicorn Drive to execute his own Rider Punch Maximum Drive. It was then destroyed when Double Detective Gold Xtreme's Golden Xtreme Rider Kick destroyed Eternal, along with all other T2 Gaia Drives.
 * Joker Drive: After the T2 Joker Drive was destroyed and Charlie dissolved into data completely, Sam uses the original Joker Drive in place of its successor. There is no noticeable difference in Kamen Rider Joker's form or abilities when using this Drive; if anything, it's possible the T2 Drive may grant an increase in basic power.