A.N

This is a crossover between UBW and xenoblade chronicles 2(also other XenoBlade games)

In XenoBlade chronicles 2 there was three AEGIS crystals that each had their own names logos(malos), Pneuma(mythra/pyra), and Ontos. But Ontos went missing in space and time. Do also remember that when core crystals are first awakened that don't have any memory. In UBW Shirou Emiya had no memories when he was found by Kiritsugu Emiya. So I had a idea that what if Shirou was Ontos. It would fit well together sense Shirou Emiya is OP like an AEGIS. Making Shirou reborn as Rex

This is a one shot. I might make a story like this but a continuation of this. Basically new game

A.N Over

Chapter I

It has been few years since the fifth holy grail war and the winner of the grail is dying by hands of the people he saved. The winner of the grail name is Shirou Emiya. As Shirou finally died his body dissolved into particles of light only leaving a metallic Colored Crystal in a shape of a cross and after a few moments the crystal vanished. Because Shirou's had such a strong resolve to save he was reborn.

(Rex's POV)

As Vandam sacrificed himself to protect me from Malos. I heard voice in my head asking what do I seek. I seek a distant Utopia, is my answer. Then remember who you truly are, the voice said. I remember who I am I am a Sword and I am ONTOS the third Aegis, I thought as A metallic colored Crystal that was shaped like a cross appeared and imbedded itself into my back. I toss My weapon aside not noticing that it transformed. Also that Pyra transformed into Mythra. So you finally decided to reveal yourself Mythra, Malos said. I didn't hear him. Malos you have done something you will regret, I say. Malos looks at me and smirks. Malos asks me how I will regret this. You should know Malos after all you are a Aegis even though you are weakened, I said as I was engulfed in a metallic light. When the metallic light that engulfed me vanished it revealed me in a suit that looked like his but in a metallic red color with a dagger in each of my hands. These daggers are known as The Rule Breaker. What are you, Malos asks me. Malos I am a aegis like you and Mythra, I said showing him my core crystal in my back. Seemed to freeze when he saw the crystal. I want to fight you at your true strength So I will fix your Core crystal, as said this his core crystal fixed itself. I will let you have the first attack kid, Malos said after his core crystal was fully repaired. Okay Malos, I said with a smirk on my face

I am the bone of my sword

Steel is my body

Fire is my blood

The area around me and Malos started to distort itself

I have forged countless Blades

I fought countless battles

The air around the battle became heavy

I don't know Victory

Nor

Loss

I am not known to Life

Nor

Death

So as I pray

Unlimited Blade Works

The area around me and Malos became a land of endless blades

where are we, Malos ask not noticing that I vanished and appeared behind him. Stabbing him with The Rule Breaker causing him to return to his core crystal. I picked up his core crystal.

The land of endless blades vanished and I was back to where I was before