It all started when Davis overheard a conversation between Izzy and Ken. Normally he paid little attention to their technical discussions as they were usually as hard to understand as boring, but that day's topic was way more interesting than usual: How wild digimon could get stronger without a partner.
A human partner could temporally evolve his digimon by sharing his energy and the digivice's, but wild digimon were capable of doing it permanently, or growing strong without evolving.
Izzy theorized digimon got stronger by defeating others, but Ken added there were strange energy sources that could increase their strength a lot and instantly, the Data Sources.
They were really rare, and usually the digimon who ate one become so strong they became a strong Mega/Supreme. Ken had found only one when he was the Digimon Emperor and used it to create Kimeramon, and probably was used for most evil digimon to become that strong.
Growing strong without effort. The idea was appealing for Davis, who was tired of being in Takeru's shadow: He had defeating him again and again in basketball, Kari seemed more interested in the blondie than himself, after battling Kokomon in America his Patamon was now capable of evolving into Seraphimon, matching Imperialdramon's power... he had better marks, perfect hair...
...And, of course, those extra ~10cm/4" in height. Davis hated so much having to look up to his rival.
First, Davis thought in getting a Data Source to make Veemon stronger than Patamon's final form, even without DNA evolution with Ken... but later, started wondering what would happen if he used it on himself, as his body was as digital as a digimon in the DigiWorld. Would it make him stronger, smarter than TK? Taller?
Taking advantage the genius had a lead to one Source but they were too busy to check it at that moment, Davis raced to the Digiworld alone to get it, as the others wouldn't approve it.
He found it in the center of the derelict castle of the Dark Master. It was a shining ball irradiating light. He took it, and the orb kept floating between his hands.
"How do I activate it?" Davis tried everything: shaking it, yelling "Digiarmor energize", shaking it again... minutes were wasted.
Then, a few former servants of Piedmon who hid in the castle attacked the intruder. They were Perfect/Ultimate digimon, so ExVeemon couldn't stop them.. it seemed it was the end... until Mr. Perfect appeared, and his perfect Magnaangemon vanished the bad guys with the perfect Gate of Destiny.
"Davis, are you okay?"
Davis, fallen into the ground, just nodded. He felt too humiliated to answer.
"What were you thinking, going to a dangerous place without telling us? The others were worried sick!"
"Don't tell me, Mr. Perfect..." Davis thought while the blond boy kept scolding him "Next time I'll be hero who saves you and lectures you, after using the Source... wait, where is it?"
The Data Source had fallen on the floor, and slowly rolled towards Takeru.
"Noooo...!" Davis saw the magic ball, but before he could stand up and catch it the Source hit Takeru's feet, releasing light as it was absorbed by his body.
"Mm? What was that?" Takeru had only noticed the flash of light, but didn't know what had caused it. He also saw his teammate sobbing on the ground and felt a bit confused. "Sorry for being so harsh on you." Takeru tried to comfort him, misunderstanding the reason of his sadness, making Davis felt even worse.