Sword of Logos is a secret mysterious organization formed by knights of King Arthur's time. They were sworn to protect the Almighty Book and keep the peace throughout the realms. 

Each one of the members is a swordsman of an assigned element alongside their Spirit Book partners. They are to be known as a Kamen Rider

Merlin: The Founder of Sword of Logos, one of the first humans to ever discover Wonder World, and one of the original creators of Holy Swords and Wonder Ride Books. He was the Wizard that guide King Arthur and other humans to build the Camelot Kingdom in Wonder World. Merlin fought against his former apprentice and went missing after the war has started.

Sophia: An ancient Mystic and co-founder of Sword of Logos alongside Merlin. She was an apprentice of Merlin. After her master went missing, she continues to protect the balance of the world and finished what her master has done.

Allen: A Magician in Training, Apprentice of Merlin, and Now Apprentice of Sophia. He helps and guides the Swordsmen of Swords of Logos to fight against the Megiddo and the darkness. He's in a secret relationship with Nari.

Kaito Daishinji: The Holy Swordsmith of the Guild. He mends all the swords and analyzes all the Wonder Ride Books.

Nari: She's a mysterious magical being. She said she was saved by Merlin alongside the very First Saber. She somehow has a connection with the past of previous Master Logos and the Megiddo. She's in a secret relationship with Allen.