With the discovery of a strange sword inside the storage room of the Wandering Sea, Ritsuka starts to train with it yet soon discovers that someone dangerous is tracking it.

"Master, are you ready for your next session?" - Artoria asked while she was eating at the cafeteria.

"Yeah, who's my teacher today? Is it Gawain, Muneori or EMIYA?" - the Master asked while drinking a cup of coffee.

A few weeks after returning from Fairy Britain and while helping Mash do clean up in one of the storage rooms of the Wandering Sea, Ritsuka came across a strange sword in a wood box. The sword seemed mostly normal, yet they soon discovered it had strange characteristics.

For once, it increased the users capabilities to superhuman levels, allowing the Master to fight toe to toe with his Servants, but the most important ability the sword had was that it allowed for its wielder to summon energy replicas of the weapon, which could then be used as projectiles or as defense.

"EMIYA's going to help you practice with your accuracy, he said to meet him in the simulator in 10 minutes" -

"Alright, I'll go to my room and prepare, see you all later" -

As Ritsuka left the cafeteria, he felt a chill running down his spine, but he dismissed the matter and went to his room, yet as he arrived he failed to notice that someone had sneaked in, a woman.

"You're the human who found the Enduring Sword? I expected better" - she said as Fujimaru turned around to meet her face to face. She was a beautiful woman, with long black hair, eyes like emeralds and a white, golden and cyan dress, with an ornament in her head, like wings of a golden dragon.

Ritsuka wasted no time in grabbing the sword and attempting to fight, yet the woman was clearly superior in every way. Without him being able to see her, she grabbed him by the neck and pinned him to a wall.

"You're slower than him, as I expected" -

"Don't... Underestimate me" -

With a quick move from his hand, Ritsuka slashed her hand with the sword and freed himself before shooting 5 replicas at her, yet she summoned 5 blades which crashed against Fujimaru's projectiles.

"The summons... How can you do them?" -

"I got some good teachers" -

Before the boy could attempt another strike, 5 more swords appeared behind him and pierced his arms, legs and back, causing a scream to come out of his mouth.

"Outside of him, no other user of the Enduring Sword had been able to use the summons before, you impress me boy, perhaps you will be worthy of training" -

As the woman finished saying that, the Servants busted the door open and attacked, but before any of their hits connected, the woman created a flash of light and disappeared in it. Worse of all, she took Ritsuka with her...

After being subdued by his attacker with relative ease, Ritsuka opened his eyes to find himself floating on a small lake, yet he couldn't move.

"The waters here have healing properties, don't move and they'll cure you of your wounds quickly" - the woman said, as she was sitting at the edge of the lake, her body submerged in the water as well.

"That won't be a problem, I can't move at all" -

"Then the waters are working just fine, a few more minutes and you should be ready" -

"Well, since I'm here and can't move, mind explaining to me who you are?" -

"Gladly, my name is Irelia, I'm a demigoddess and user of the Divine Sword" -

"Alright, then why did you attack me?" -

"At first, my purpose was simply to retrieve the Enduring Sword, and if I wanted I could've killed you on the spot, yet when I saw you using the summons, I decided against it. Why simply seal the Sword when I can train its next wielder?" -

Irelia then started to walk towards Ritsuka, who was finally able to move again, noting how shallow the lake was.

"I'll train you to be the future user of the Enduring Sword, better not disappoint mortal" -