Here we come to save the day!

Shirou Emiya was patrolling downtown Fukuyi that night unbeknownst to Illya and Astolfo. Both his and Caster's attention are caught by the loud explosion coming from the city. "Let's go, Caster!" Shirou says as he breaks into a sprint. "Right you are, Master!"

The unlikely duo arrive to the scene of Illya's, Astolfo's and Lancer's fight first in time to see the blue-armored, black-haired servant facing off against what appears to be an 18 year old white haired girl. His eyes are filled with killing intent as his blade is already moving in to kill the girl. There's only one way you can help. Your remember Caster's words and speak them without hesitation

"Time alter, double accel." You feel the time around you slow to a crawl. Lancer's blade moves in slow motion. You move quickly to stand in front of lancer and block his blow. Your arm takes the blow, deflecting Lancer's blade as of your body was made of steel. Lance backs away, your arm not any worse for wear. You'll have to thank Caster later for her timely intervention. But for now, Lancer backs off.

"You do know she is a master, right?" Lancer says with spite. "That doesn't matter!" You retort. Nobody deserves to be killed. Her servant is gone, so leave her alone!" You exclaim. "Pffff, I don't want to fight another servant right now anyway, that wasn't my master's orders. But rest assured next time we meet, I'll kill you for good." Leander threatens as he disappears back into ethereal form.

You look at the white haired girl. "Thank you, onii-chan~ I knew you'd be here for me." You look shocked as she calls you as such. "My name is Illyasviel von Einzbern, but I'd like it if you would call me Illya!" She exclaims cheerfully. "Don't be afraid. I'll explain more later, be for now we should get our of here." You breath a sigh of relief as the girl follows you back to your home.