A Certain Scientific Omnitrix: New Testament. Vol. 1.

Rin

"The lights are flickering the lights are flickering.. on and off.. on and off.. Mordred you bastard.. on and off.. Morgan you ass.. on and off.. where is my master.. are you my master.. where is my master.. are you my master?"  The girl hugged her shoulders, her eyes darting back and forth as she sat in the armchair in the lobby of the mental hospital..

The hospital worker looked at Ben, Touma, Helen, Birdway, and Mikoto with a raised eyebrow. "So.. how are you related to Jane Doe again?"

"Her name's um.." Ben's memory immediately flitted to the strange black knight that had saved him from Berserker years ago. "Saber..! Yeah.. Saber..  she's actually just a friend of mine.. the one whose related is.."

"ME!" Birdway sniffled, playing a little distraught 12 year old perfectly as she put on her cutest expression. "Oh Saber! Big Sister, I've been looking for so long, and here you are!!"

The girl stared at Birdway uncomprehendingly. 

"We're just friends really." said Helen. "He's Ben 10.. surely you can understand he meets a LOT of people.." 

"Right.. of course.. so it's Saber.. and.. last name?" Asked the man.

"Pendragon." said Ben immediately. "Uh.. Saber Pendragon.. this is Leivinia Pendragon, her little sister. Her mom's letting me babysit her while we visit Saber here.. "

"Well.. I have to say I'm glad she has SOME family.. she's one of our most fragile patients.." said the man. "I don't know what happened to her, but chances are she'll never recover from whatever ordeal she went through..  Can you believe how she looked when we found her? Her skin was super pale, her eyes were yellow and she looked like she got real beat up.. said something about saving a boy with a watch from a guy named.. Ser.. something.. I don't know.."

Ben felt his heart drop. They barely knew each other.. and this person had been dead intent on protecting him.. if this was King Arthur, she was every bit as righteous and selfless as the legends said.. 

"How is he.. I mean.. she alive?" Ben whispered as the worker walked away to give them some privacy. 

"She's a Servant... a special servant.. but she is one nonetheless.. " said Paradox, appearing as if walking out of thin air. "A Masterless Servant actually, that one is a bit complicated..  Servantis experimented on her and eventually her mind broke beyond repair.. however, there is a way to restore her.."

Ben held out a hand to the girl, and she looked at it for a moment, then covered her head, whimpering muttering "no more.. no more.. "

Ben felt boiling fury in his stomach. Servantis was going to pay.. no.. GREMLIN was going to pay.. all of them were.. how could they do this to any person!? Nobody deserved this..

"How do we do that?" Mikoto asked, putting a hand on Ben's shoulder.  

"A Servant is unique in which their Noble Phantasm is a large part of who they are.. it restores their identity by using the Grail that summoned them to reproportion their memories." said Paradox. "If Saber is reunited with Excalibur.. she'll become good as new.. however, there's a catch, the one reuniting her must share a close bond that goes beyond time.. otherwise.. they risk turning the Servant into a pure Berserker intent on destroying everything in it's path.."

"The Forever Knights don't understand this." said Birdway. "They'll try to reunite the sword without fully understanding that they don't know or share a particular bond with King Arthur.. their leader.. the First Knight.. knew Arthur, however he didn't know her secrets.. He thought he did, without understanding that Arthur hid everything inside...  if HE manages to reunite Excalibur with Arthur.. then he'll unleash a super powered Saber Class Servant capable of leveling entire civilizations onto this world.. and even Atomix won't be able to stop her without killing her after that.."