This is my story idea of my plan writing the prequel story of Kamen rider Saber. It's tell the story of (Y/N)'s predecessor and Brave's previous in the pasts before the story has begins. It's tell the story of Saber fight against the forces of Evil alongside with the Swordsmen's ancestor and fell in love with the woman. They will appears help (Y/N) as the spirit guidance. 

Kamen rider Saber x Fire Emblem Blazing Sword: The Flames of Blade

Previous Saber name: Haruki

History: Haruki is the young man and member of Swords of Logos, he was the user of Saber and partner of Brave Dragon. One day... Haruki tried to save his younger sister from the forces of darkness but he failed and sent to the Earth realm causing his sword's emblem to be damaged unable to returns home. One day he was save by the Lorca's chieftien tribe daughter Lyn and, they're fell in love.

Love interest to Wife: Lyn

Kamen rider Saber x Fire Emblem: Sacred Stone: The Stone of Book

Previous Saber Name: Luke

History: Luke is the young noble son who is the user of Kamen rider Saber, he is kind and friendly to everyone and his friends. Seeing everyone as equal as friendly. One day Luke went to stop the darkness and travelling to the other realm that they're steal the crystal book. As he encounter meeting Princess Eirika and her groups party and he decided to joins them. As they're grew in closer.... They're fall in love.

Love interest to wife: Eirika (Plus Tana has confessed feeling to Luke but he rejected to her and have feeling for Eirika.)

Kamen rider Saber x Fire Emblem Awakening: The Flame of Awakening

Previous Saber user: Ryuga

History: Ryuga, is known as the previous Kamen rider Saber, the Swordsman of Flame, in the past he was raised by the Troll name Blinky in the Ground Realm see him as the father figure alongside as Brave Dragon as the brother figure and in arm. As he traveled to the world in the Earth realm and he encounter meeting Chrom and his band of Shephand become as brother in arm. And their tactian Robin, as they're felt closer to fall in love.

Love interest: Robin

Kamen rider Saber x Fire Emblem Fate: The Flames of Revolution

Previous Saber Name: Ryuga

History: After Ryuga sacrificed to save his lover Robin at the end of the story, one day... He was mysterious revived at Nohr and founded by Prince Xander and took him in. He has no memory of his past, excepts for his swordsmanship impressed by royal family and decided to take him bodyguard as Corrin. As they're spend close together and the princess of Nohr fall in love with him. (P.S this is direct sequel from Saber x Fire Emblem Awakening) 

Love interest: Corrin.

Ryuyga's love Interests to wives: Robin and Corrin

Kamen rider Saber x Yona of the Dawn: The flame of Knight and Princess

Previous Saber name: Wilkin

History: Wilkin is the young knight, member of Sword of Logo, the user of Saber, the Flame of Swordsman and he has reunited of his childhood friend his first love, Yona. Knowing she has love to Su-Won, one day she found out her father was murder by her cousin and he reveals wanted to become next king and use the Power of Books to take over the Wonder World but save by Wilkin to save her. Joins Wilkin with Yona and Son Hak to stop this and save the worlds.

Love Interest: Yona

Ended

Well that's all guys! This will be my future prequel story for my Kamen rider Sabers story of how all previous Sabers has journeyed to their new friends' quests to save the worlds. And.... How they're fall in love.