This is how Kentarou first stumbled across Sparkz.
Sparkz is not from Ken's village at all; in fact, he was teleported there by his advisor from his own home village. Next in line to be the Cardinal of his village, Sparkz was in-training under his advisor, mastering control of his innate magical abilities from his racial heritage. His home village is on a medium-large island a bit away from the mainland of the Mukai Kingdom. Not many travelers travel to this island, so his species is not seen much at all, and hardly anyone knows exactly what he is. This is a village of Sparkz's species, Carlinoxes, that happens to thrive on magic-related technology and discoveries. Their village is governed by what they title a Cardinal, whom is deemed most fit to run the village with his magical abilities. Sparkz's advisor was initially deemed the most worthy as next in line for that role. However, as the advisor got wind that 6-year-old Sparkz was found to be the new next suitable for the role of Cardinal, due to his quick mastery of using magic and the sheer power behind it, the advisor betrayed Sparkz and after hitting him on the head and knocking him unconcious with forbidden magic to give him amnesia, he also used a teleportation spell that sends the target somewhere random in the world. If the next suitable Cardinal isn't present and found within a month, a followup is chosen to be, which naturally would fall onto the advisor himself.
Sparkz happened to land into Ken's home village, still unconscious. 7-year-old Ken stumbled upon him as shown here, and quickly seeked help, carrying him on his shoulders to his grandmother's (also his house, as she's the last of his family that remains in the village) house. Ken's grandmother is a sweetheart, so naturally she couldn't just leave Sparkz outside, and decided to take him in and nurse him back to health. She changed him from the robes of his village into the garb of their village. Sparkz was unconscious for a good 3 days before finally coming to, and Ken was by his bedside, being the first person he's ever seen. As he had amnesia, Sparkz could only ask two questions: "Who are you?" "Where the heck am I?" Only able to smile, Ken was relieved that he was still alive after being out for so long, and gave him a hug, saying "I'm glad you're awake! I'm Kentarou, but people just call me Ken. You're in my home village. What's your name?" Sparkz was uneasy with the hug because he didn't know anything about Ken yet, besides his name now, but shrugged it off and tried to remember his name. It was a bit foggy, but he was able to sound it out. From then on, he and Ken just hit it off and became best friends over time Ken would continually try to get Sparkz to remember what happened, but to no avail. It's as if that memory was permanently lost...
And...there you have it. Of course, this is going to be the intro to the game, so you'd get to see it all in action.