Sid (錠前ディーラー シド Jōmae Dīrā Shido) sold Lockseeds to the youths of Zawame City to facilitate their Inves Games. After receiving his Genesis Driver, Sid used the Cherry Energy Lockseed to become Kamen Rider Sigurd (仮面ライダーシグルド Kamen Raidā Shigurudo). However, his craving for the Forbidden Fruit ultimately led him to his demise.
Prior to the event where Sid was recruited into Yggdrasill, Sid was formerly a thief who was being attacked by few Elementary Inves after stealing money and jewelry. On that day, he was found by Ryoma and offers him to join Yggdrasill in which he accepted, thus he became a Lock Dealer for an Inves game.
When Yuya approached Sid, he was given the Sengoku Driver, which then led to Yuya ending up in the Helheim forest. He is also the last person who saw Yuya, before he mysteriously disappears after gaining the belt from him. Kouta and Mai visits him in Drupers and asked him about the Sengoku Driver. He tells them that the belt works for whoever the first to wear the belt was, which only locks to the first wearer.
Sid then would give them Lockseeds to help them win, but Kouta and Mai couldn't buy the Lockseeds. As he hears that Team Baron is losing badly, Sid offers Kaito the Sengoku Driver, along with the Banana Lockseed. Sid later appears just as Armored Riders Gaim and Baron are about to fight as he changes the rules when more Armored Riders joins the game and gave each of them a Lockvehicle.
Mitsuzane approaches Sid and buys a Sengoku Driver from him. Sid then discloses that he knows about his brother and father and how that they are members of the board of the Yggdrasill Corporation. Mitsuzane convinces Sid to give him the belt, which made Sid take a liking to the boy. He then left the belt behind and told Mitsuzane to return it, if he was his old self. As he overhears from Hideyasu that they want to be on the same level as Kaito, Sid offers Sengoku Drivers to Ryoji and Hideyasu.
In Takatora's limo, Sid shows Takatora a list of "test subjects" that have the Sengoku Driver, but he decides not to see the list as Sid leaves the car. Sid then begins plotting something, as he knows that Takatora's younger brother is a user of a Sengoku Driver and that he could use this knowledge to his advantage. How he plans to exploit this information for his own intentions is unknown at this time.
Sometimes later, Sid gives the Sengoku Driver along with the Durian Lockseed to Sonomura, the leader of Team Red Hot. Sid visits Team Gaim's garage as he would ask if Mitsuzane stole the Suika Lockseed. Mitsuzane tell Sid that he might steal the item from his brother and saying that he and Sid are "friends". The team leaders approach to Sid as they want to get Lockvehicles, but Sid says that they are not ready until Christmas.
Later, Ryoma ask Sid about his plan giving Lockvehicles to the Armored Riders, as Sid reply to him that he have no clue.After the Armored Riders finish their game in the forest, Kouta and Mitsuzane give him a box of Lockseeds and the former tells Sid that they are no longer their test subjects. After Kouta and Mitsuzane leave, Sid remarks that "it's time to close up the shop."
Later, Sid was in a meeting along with Takatora, Ryoma, and DJ Sagara (as a hologram) about the disease that the citizens are having. Sid and Takatora were in a meeting about the Genesis Driver, until Takatora got a call about Hase's madness, which ended their meeting. He later arrives along with Takatora, Ryoma, and Yoko as they transform, and he, as Sigurd, fought the Inves without mercy. After he finishes off the Inves, he cancels his transformation and reveals himself to Kouta and tells him that he was doing "justice", before the Kurokage Troopers appear and take Kouta away.
Before Kouta could enter the Crack, Sid appears to stop him by force. They transform as they start fighting when they entered the Crack. He manages to overpower Gaim, but Baron arrives as they overpowered Sigurd before they escape. As he prepares to finish of Gaim and Baron, Marika stops him as Yoko tells Sid that she is following Ryoma's orders. Later, Takatora was upset about Sid giving the Sengoku Driver to Mitsuzane without his permission as Ryoma appears on screen telling his reason of letting Kouta and Kaito escape.
Ryoma then noticed that some of his equipment is missing as Sid suspects that one of their comrades had something to do with their escape. After Gaim finished off the Inves, Sid discovers where the missing items (the Genesis Core and Lemon Energy Lockseed) are.
Later, Sid got a call from Takatora about Kouta and Kaito sneaking into the Helheim forest. He, along with the Kurokage Troopers arrive in the forest and remove Kouta and Kaito from the forest. As they reentered the forest, Sid transformed to stop them, but they flee. While searching for them, Gaim surprise attacks them as Sigurd stops Baron, however he was overpowered by Baron in Suika Arms. As Kaito enters the Yggdrasill tower, Sigurd appears to stop him, but Ryoma appears as he tells him that Kaito is their "guest".
Later, Sid discusses with Yoko about Yggdrasill's plan and the future that holds the company. After hearing Kaito's opinion about the golden opportunity to destroy the weak from yesterday, on the next day, Sid investigate an attack on their troops by an unknown assailant, who they believe to be Kouta's doing, Later night, Sid goes home, but was suddenly ambushed and attacked by a mysterious Armored Rider who can produce Helheim's power, Idunn, as Sid is about to transform in his weakened state, but the Rider getts away before Sid could transform, thus, fading away, as he is found and sent to the hospital in the next day.
Sometime later after recovering from the bruise he received from Idunn, he discussed with Ryoma about killing Kouta as he noticed that Kouta would get in their way of creating a perfect world. Ryoma says as long as he gets data Sid can do as he pleases. Sid sold the Lockseeds to the criminals and found Kouta. He told Kouta about their (but Sid lied that Yggdrasill is the culprit) true goal was to bait all of the Helheim creatures and destroy them alongside Zawame City, stating that it was true heroism which angered Kouta.
The misunderstood and enraged Kouta fought him with Orange Arms at first and Sigurd easily defeated him. However, Kouta stood again and using it Jimber Lemon Arms and Sigurd was defeated by the enhanced Burai Kick from Gaim. Disbelieving in his defeat, his Cherry Energy Lockseed was confiscated by Kouta. Before Sid could be beaten up by Gaim, Ryugen helped him in the shadows by calling a Elementary Inves to help him escape.
Later, Mitsuzane told the group that DJ Sagara is responsible for helping Kouta to continue fighting. The group didn't believe him as he also informed the creatures that were more dangerous than the Inves, as Sid, along with Ryoma and Yoko suspected that Kouta knew about the Over Lords. After the meeting, they were wondering about Sagara's identity as Ryoma ordered Sid to stop Kouta. As Gaim enters Helheim forest, Sigurd arrived to stop him as he uses his own Lockseed to summon the Suika Arms to fight Gaim. However, Gaim easily destroys the Suika Arms with Kachidoki as he changes into Jimber Cherry Arms and quickly attacks Sigurd as he continues to search for the Over Lords.
Sid walked with Ryoma and Yoko into Ryoma's office and was shocked to see DJ Sagara sitting there as he informed the group of his origin. Sid, along with Yoko enters Ryoma's office as he suspect that the Over Lords had made their move. He then enters the forest and attacked Gaim, however Zangetsu Shin stopped him by force as he lets Gaim search the Over Lords. They cancel their transformation as Takatora decides to let Kouta join their group, much to Sid's surprise. The plan of eliminating Takatora was a success, however Sid reveals his true colors to Ryoma and Yoko, and eventually he destroys the Crack lab (and also most of their Lockvehicles) to find the forbidden fruit before Ryoma does.
Later, Sid was found by Mitsuzane as he asked him to help him to stop Kaito from searching for the Over Lords while he deals with Kouta. He manages to find Baron as they fought, however Sigurd was weakened by Baron in Lemon Energy Arms. While fighting Baron, Mitsuzane informs Sigurd that one of the Over Lords had arrived where he and Gaim were as Sigurd was about to escape.
Sigurd arrived where the Over Lord, Deemushu was as he fought the monster, however Baron appears and they resume their fight. Overpowered by Gaim and Baron, Demushu managed to escape as it enters the Crack where it leads the creature to Zawame.
After the Over Lord enters Zawame, Sigurd and Zangetsu Shin encountered another Over Lord, Redyue as he demands from her the Forbidden Fruit. The Over Lord then fought them, but loses the match as she lets them follow her to the location of the Forbidden Fruit. Once in the ruins, Sid meets Rosyuo and is surprised to see Takatora as he transforms and fought the Over Lord. Overpowered by Rosyuo, Sigurd's equipment started to dissolve as Sid meets his end when Rosyuo blows him against a rift between walls and subsequently crushes him by having the walls converge on him.
Sometime later, Sid was revived by the return of Kamen Rider Mars in the form of Kamen Rider Jam. With his Genesis Driver and Cherry Energy lockseed powered up, Sid left Zawame City behind, heading for unknown parts.
One of Takatora's subordinates. At first, Sid is loyal to him in carrying out tasks. In the beginning, he plays a major role in Inves Games, where he sells Lockseeds at the Drupers in order for Yggdrasill Corporation to conduct an experiment on the Lockseeds. When Mitsuzane becomes Armored Rider Ryugen, Sid tries to keep this as a secret for a while at the same time gains an awareness of the boy's darker personality.
Like his employer, Takatora, Sid also shows poorly-veiled arrogance and condescendingly refers to the other Armored Riders as immature "children" and he along with his friends as the "adults", despite the fact that two of them are of legal age. He also seems to be calm and act cool in dangerous situations, as seen when Takatora was furious at him for keeping Mitsuzane's double life as an Armored Rider a secret.
He also seems to have some degree of being a sociopath, as he takes great amounts of pleasure smacking around those weaker than him as Sigurd, as well as taking bloody payback when he's smacked around. When enraged or annoyed in a fight, he tends to not hold back on his strength for payback, not caring if he could potentially kill the one he's fighting. He also takes great delight in messing with people's heads, and shows no empathy to anyone but himself.
- Height: 203 cm.
- Weight: 105 kg.
- Ability Perimeters:
- Punching power: 14 t. (19 t. Revived)
- Kicking power: 18.9 t. (25 t. Revived)
- Maximum jump height: 24 m. (40 m. Revived)
- Maximum running speed: 100 m. per 6.1 sec. (4.1 sec. Revived)
Cherry Energy Arms (チェリーエナジーアームズ Cherī Enajī Āmuzu) is Sigurd's default cherry-based armored European Viking/Archer form. Accessed through the Cherry Energy Lockseed, this form bears the Cher Headpiece (チェルヘッドピース Cheru Heddopīsu) helmet with the Steering Eye (ステアリングアイ Sutearingu Ai) visor. This form debuts in episode 14.
While assuming Cherry Energy Arms, Sigurd dons the Cherry Energy Armor Part (チェリーエナジーアーマーパート Cherī Enajī Āmā Pāto) and his Arms Weapon is the Sonic Arrow.
This Arms' finisher is the Sonic Volley (ソニックボレー Sonikku Borē): Sigurd locks the Cherry Energy Lockseed into the Sonic Arrow and fires a powerful arrow shot that when it hits a target pierces into their body, causing twin cherries to swing around and crush the target in between them until they explode upon collision. </div>
- Height: 203 cm.
- Weight: 105 kg.
- Ability Perimeters:
- Punching power: 12 t.
- Kicking power: 22 t.
- Maximum jump height: 60 m.
- Maximum running speed: 100 m. per 6.1 sec.
Kiva Arms (キバアームズ Kiba Āmuzu) is a Legend Rider Arms based on Kamen Rider Kiva's Kiva Form, which is accessed through the Kiva Lockseed.
While assuming Kiva Arms, Sigurd dons the Kiva Armor Part (キバアーマーパート Kiba Āmā Pāto) and he does not possess an Arms Weapon. This form was assumed during Sigurd's temporary use of a Sengoku Driver.
- Sid owns a custom-made Lockseed, never officially named in the show but referred to as the "Sid Lockseed" in production materials. Initially Sid was only seen carrying it around during Lockseed deals, he later used it for the first and only time in battle, using it through the Sonic Arrow. The Lockseed is capable of generating Arms Weapons of other Lockseeds, though he was only seen using it to summon three Suika Arms.