An early start

"Hmm hm hmmm..." the young murderer hummed softly as he drew the circle in blood. Beside him a child cowered, tears in honey brown eyes. His red hair was splashed with blood, drying in ugly spikes. "Hey kid, this blood is getting all dry. Let's add some fresh!" He squatted over the child with a knife. The child trembled in fear, unable to make a sound as his skin was cut and blood welled up. Laughing maniacally, the serial killer finished his circle, following the tattered pages of his book. "Fill fill fill – uh, four times or five? Fill fill fill fill fill… ah, that makes five times!" The young man laughed, and began taunting his young victim. He didn't notice the summoning circle behind him beginning to glow a soft golden light…

In this particular timeline, Uryuu Ryuunosuke made two critical errors.

The first was to pick a house two doors down from the usual one. The second was to partially draw the summoning circle in the blood of an untrained but potentially powerful magus. Drawing a circle partially in their own blood was a common magus trick to ensure proper resonance. While the boy had only one Mage Circuit active, that was one more than Ryuunosuke had.

The Grail aligned on the boy and, after a moment of searching, selected a Servant. But before it was released, the Servant was altered to better suit its' Master.

Servants did not have to be adults, after all.

"Wha - ?" Ryuunosuke really wasn't expecting it to work. He'd tried many times, after all. So he was shocked and very happy when the circle exploded in gold mist. "So cool," he breathed as he watched the circle fill. The little boy stared with wide, honey-brown eyes, his terror momentarily forgotten.

The golden mist slowly cleared and eyes opened as the newly summoned Servant surveyed the situation.

"Um…" Ryuunosuke looked down. Way down. The 'demon' looked up. "This is totally not how I pictured this going," Ryuunosuke said after a moment, running a hand through his hair. Then he brightened. "Are you a kid demon?" Hey, maybe he looked like that to lure people in! It'd work great! The kid blinked again.

"No." …Aw snap. Another thought suddenly occurred to Ryuunosuke. This little white kid would be great fun to kill! "Who are you?" The kid asked and the serial killer decided to play along.

"I'm Uryuu Ryuunosuke! What's your name?" he asked, squatting down so he could easily look the kid in the eye. His eyes were a super pretty color, they looked like blue topaz. How would they look when he pulled them out?

"Karna," the child said and Uryuu smiled sunnily even as he noticed the kid seemed strange. Maybe autistic or something? Sure not very friendly. "If you wanted to summon, you made a mistake."

"Huh?" Ryuunosuke made a questioning sound as a palmed a knife. The kid ignored him, walking towards the red-haired kid. "Oh, hey, do you want to eat him?" Uryuu asked, figuring he'd give it a try. Maybe this weird white kid was a werewolf or something, who knew? The kid ignored him, squatting down beside the tied-up kid and pulling off the gag. His fingers seemed to saw right through it, it was weird.

"Are you my Master?" Hey, was he talking to the brat? Ryuunosuke sighed softly, deciding he'd summoned a dud. Well, it would still be fun to kill him! He suddenly slashed out with the dagger, aiming for just the right spot to incapacitate the kid without outright killing him. Ryuunosuke wanted to have fun –

And then Uryuu's eyes went wide as his wrist was caught and unceremoniously broken. The wet crack of breaking bones wasn't unfamiliar, but it was unusual to have it coupled with searing pain. He stumbled away from the white kid in shock and suddenly saw something dangerous in those empty aquamarine eyes. Something that reminded him of himself.

"Yes. Yes!" The red-haired kid shouted and the white haired kid – Karna? – nodded.

"In the class of Rider I, Karna, accept your contract," he said and Ryuunosuke swallowed. What the hell was going on? Why would his demon pick the kid over him? "Master, what shall I do with this man?" Honey brown eyes filled with tears.

"Kill him," was the command and Ryuunosuke stared in amazement, not even thinking of running away, as the little demon raised a hand. Fire filled it and it was hard to look at, like looking at the sun. So bright and pretty!

Then he felt, not pain exactly, but pressure and heat. Looking down, Ryuunosuke saw that roughly half his chest was missing. All that was left was a lot of char and he could see the edges of bones and things. It was – really different…

Wow, this is so cool, the serial killer's fading thoughts were full of a wonder as he sank to his knees. So crazy and cool. How many people could say they'd been killed by a demon? He could! The only thing Uryuu Ryuunosuke regretted as he died was that he wouldn't be able to see what the kid and his demon would do together.

It would have to be so cool.