Isaac was the most recent holder of the title Master Logos, the elusive leader of the Sword of Logos. When his true intentions were revealed, he abandoned his title and controlled the Southern Base into war with the Northern Base, becoming Kamen Rider Solomon and declaring war against Touma Kamiyama after the latter formed a resistance within the Northern Base. Ultimately after Touma defeated him in their final battle, Storious would betray and kill Isaac.

Forms:
-Omni Force

Equipments:
-Omni Force Wonder Ride Book

-Caladbolg

-Dooms Driver Buckle

-A fragment of the Great Book: He used it to block an attack from Storious. He later used the book to banish Tassel from the Southern Base.

Powers:
-Clairvoyance: Master Logos can observe the actions of the Northern and Southern Base swordsmen, even when he is sitting in his throne. He was able to see Touma Kamiyama using the Primitive Dragon Wonder Ride Book and Ryoga Shindai ignoring his orders to fall back.

-Teleportation: Master Logos can teleport himself and others to any place that he wishes. When he uses this power, he or the subject disappears in a cloud of red smoke.

-Energy Ball: Master Logos is able to shoot a red energy ball at his enemies. He once used it to shoot down Bahato when the latter attempted to attack him, and used it on Sophia when she tried to sacrifice herself.

-Superhuman Strength: Master Logos has considerable superhuman strength. He is able to use the Dogouken Gekido with one hand, while the original and previous owners used both hands. Moreover, his superhuman strength allows him to physically overpower both Saber and Calibur at the same time while both of them were transformed, even though Saber is using Elemental Dragon form, which is his strongest form at that time. Master Logos was able to block their heavy attacks effortlessly using his stolen Seiken, and landed considerable damage to them.

-Superhuman Durability: Master Logos has considerable superhuman durability. He was able to directly withstand an energy wave caused by opening a portal unconsciously by Touma, which was very impressive as he has suffered no harm or injuries at all; that same energy wave canceled both of Saber and Calibur's transformations.

-Superhuman Speed: Master Logos was fast enough to counter all Saber and Calibur's attacks at the same time while simultaneously striking them multiple times. They were also unable to block his attacks and couldn't land a single hit on him.

-Superhuman Reflexes: Master Logos was able to fight both Saber and Calibur at the same time, while dodging their attacks with ease.

-Circadian Manipulation: By using Omni Force Wonder Ride Book's power, he can easily turn day into night (or vice versa) in his civilian form.

-Body Control: Using a red smoke from Omni Force Wonder Ride Book, Isaac can hijack the bodies of another swordsman, and have them do his bidding. All known victims still have consciousness on their action while they are under his control.

-Forced Transformation: Using the same red smoke, Master Logos can force a knight to transform.

-Great Book Fragment Powers: By using a fragment of the Great Book, he is able to utilize the following powers:

•Energy Arrow: Master Logos is able to manifest an energy bow from his Great Book fragment, and shoot an arrow from the Southern Base to the Northern Base. The arrow can split into multiple smaller arrows, and is strong enough to severely damage the barrier of the Northern Base.

•Seiken Summoning: Master Logos can summon Seikens to his side via using a book portal, although it is unknown how many he can spawn.

•Longetivity: Due to the Great Book Fragment, Isaac can live a little longer than an ordinary human, but not equal to Tassel or Yuri, when both of them can live for thousands of years.

Abilities:
-Master Swordsman: Being the leader of the Sword of Logos, Master Logos is a master swordsman, being extraordinarily skilled in swordsmanship. He is able to competently wield both the Dogouken Gekido and the Raimeiken Ikazuchi simultaneously, uses the Seiken's special ability to attack opponents. Even without being transformed, he was able to effortlessly fight Saber and Calibur at the same time while both of them were transformed, and completely overpowering them. With his newly obtained powers from the Omni Force Wonder Ride Book, he was able to fight five Riders simultaneously.

-Expert Tactician: Isaac is an expert strategist and can think of intricate plans tens of years into the future. He formulated and initiated several events in the background involving the Sword of Logos, including Hayato Fukamiya's betrayal and unleashing Bahato from the Book of Ruin, all so he can get his hands on the Great Book and become a god to rule the world.

-Master Manipulator: Master Logos has been shown to be charming and persuasive, using his status and knowledge to coax allies and enemies alike into doing his bidding. These manipulative tendencies were what allowed him to maintain his lies for decades, while he secretly worked from the shadows to gather pieces of the Great Book.

Weaknesses:
-Ankokuken Kurayami: Once Kurayami's sealing power is unleashed to its maximum capacity at the cost of its user's life, even Solomon's power is no match against it.

-Strong Will: Solomon can force a Wonder Ride Book user to do his bidding in their Rider form. However, a user who has a strong will can resist and even break free.
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Personality:

As Master Logos, Isaac appeared to be a wise and calm leader who guided the swordsmen in the Sword of Logos to protect the world by any means. Unlike previous holders of the title, however, Isaac betrayed the rules, defied his sworn duty for his own nefarious goals, and had a maddening god complex. He was obsessed with bringing ruin to the world and recreating it in his own image, which would be nothing but a crazy nightmarish hell as humans suffered, killed, destroyed, and fought; he wickedly found it all exciting when confronting Tassel, and later the Kamen Riders from the Northern Base. He desired to fulfill his goal simply because he viewed the current world as boring. This dangerous obsession stemmed from the fact that his predecessors were reluctant to use the power of the Great Book for their own gains, despite knowing its existence; because of this, Isaac deemed them pathetic. His hatred for someone to follow their bloodline's order was even shown to the Shindai siblings once they betrayed him. Despite being a psychotic god-wannabe, he kept his true ambitions a secret from all of his followers. While he did put up a calm face, Master Logos often let his true unhinged, maniacal and insane nature slip in private, especially when around Storious. He was willing to take any underhanded action that would advance his selfish goals, being completely callous and uncaring to the destruction that his plans would bring. As an opportunist, Isaac was shown to have a clear grasp of people's personalities and exploited them to his advantage, manipulating both heroes and villains like fiddles so he could ascend into godhood by taking all of the Seikens and Wonder Ride Books. He had successfully risen to the top of the Sword of Logos in a very short time, even eliminating the 4 Wise Gods in secret just to ensure that they would not stand in his way. He corrupted Hayato Fukamiya 15 years prior into believing what he was doing was truly going to save the world. He also took advantage of Touma's break-in into the Southern Base so he could lead him to the forbidden book containing the Primitive Dragon, all while playing on his frantic emotions to get back Luna, who was a key factor in recreating the Great Book. He released Bahato due to their goals being similar, and even used the loyalty of the Shindai clan, mainly Reika and Ryoga Shindai, to have them serve him. He allied himself with Storious at the same time and used Luna only for completing the Book of Omnipotence.

Isaac had a sinister air of happiness and confidence whenever things go his way, and was often seen laughing or boasting about his actions. His god complex was taken to the extreme upon obtaining the Omni Force Wonder Ride Book, in which he called himself an actual god. On the other hand, Isaac was not without a fatal flaw; his aforementioned god complex, coupled with his hubris, nihilistic and destructive worldview, ultimately contributed to his eventual downfall. This started with Touma using the Haouken Xross Saber to continually set back his plans; once he was beaten time and time again, he refused to accept defeat in suffocating darkness while proclaiming that his story had yet to begin, resulting in him being reduced to a screaming and deranged wreck of his former self. When he was later betrayed before being quickly killed by Storious, Isaac was livid over how things did not proceed in his way.

In the end, Issac died a karmic death; he wanted to use everyone like pawns so he could ravage the world as a god simply because he was bored, but his god-like power was destroyed right before his very eyes and spent his last moments as a whimpering wreck unable to comprehend his fear; he was then killed ingloriously by the chessmaster he believed that he could control like anyone he believed to be below him.