Kariya Matou gazed at Berserker. Oh, he knew he did not summon Lancelot since Berserker was female, and he could see it was female despite its grotesque body. He couldn't even disguise the beast as one arm touched the ground and the other arm was a thin blade. In fact, its neck was attached to one of its shoulders, and it seems to be bleeding a lot. Also, there seems to be a red streak in her hair.
"Really, one simple task and you couldn't do it properly." Zouken looked as a red thread drifted free from the shard of the Round Table. "Still, you did summon Berserker, so you aren't fully worthless. Now, go and fight."
"Just make sure to keep your promise, Zouken." Kariya muttered, knowing this wasn't the last time he would be in this house.
10 Years Later
"Onee-chan, you should summon your servant. Berserker" Before anyone could respond, a great blue light flew down and hit the ground, and Saber quickly grabbed Shirou and Rin and pulled them away. In the crater, there was a girl in a white armor of some sort, a mix of samurai slacks and actual armor. On her shoulders were two giant shoulder pieces that looked like eyes. She also had what seemed like horns in her hair, and she carried a red sword that looked like half a pair of scissors. Also, she had a red streak in her hair.
"Oh? You didn't tell me the human summoned Arturia again. This is going to be lots of fun."
"That Berserker's talking..." Rin realized. "She must still have most of her mind intact, so her stats shouldn't be hi-"
Berserker waved her sword, and Rin flew off with the wind. Saber managed to hold onto Shirou and stand her ground. "How did you know...wait, you're Ryuko, aren't you? How is it that you look different despite being summoned in the same class again?"
"Oh, the first time, I was very pissed off but I got over it." Berserker said nonchatantly. "Then I find out I wasn't exactly human, and so I went to find the answers. I was captured, but then I was taught the secrets of a happy life. Isn't that right, Illya?"
As Illya blushed, Berserker stood before Saber in an instant and cupped her cheeks. "I hate you so much, I love y-"
An arrow flew into Berserker's head as Saber quickly backed off. Berserker growled as she pulled the arrow out of her head and the wound heals. "Really, you thought that could hurt me?"
"Oh no, I was just which era you came from." Archer revealed himself. He summoned two blades in his hand, one a black katana, and the other a purple blade that made Berserker very angry. "I just have to wonder, are you stronger than Hercules?"
((So Ryuko summoned as Berserker of the Holy Grail War...twice.))