"Natural Digivolution is extremely difficult to undergo," Norn explained. "There are multiple stages. The first, after being born, is Fresh. Then is In-Training, and then Rookie. Naturally speaking, these stages can be obtained by growing stronger. Consider it 'growing up'. However, the more powerful forms require data to obtain. The only way to do this is to take it from other Digimon... in other words, by fighting."

Ryūko paused, biting her lip. "I see," she said. "By taking the data, does it kill the oponent?"

"It can," said Norn. "At the very center of every Digimon's physical form is something called a Digicore. A Digimon can survive severe trauma as long as the Digicore isn't destroyed. But if a Digimon's Digicore is absorbed..." Norn trailed off.

"I... I see," Ryūko murmured.

"Taking a Digicore boosts a Digimon's strength much more than just taking all the other data. Because of that simple fact, some Digimon are willing to kill their opponents for the sake of power. That is why you are all here: to stop those who do that."