Idea

"What?" Ryan frowned. "Lizards can become dragons after they reach a certain level of corruption?"

"I don't think that is the case…" Femradiel said. "Don't you remember? Corruption is deeply related to dark feelings. The key here is the words lizardmen, mana and corruption. Those three probably are necessary for a dragon to be born… interesting."

 Finally, they obtained some information about the dragons' origin. Still, after that news, Ryan couldn't help but worry about that intel… to think that other living beings could corrupt others… Ryan thought that only demons could do that, but it seemed that things were different. The system didn't mention any demons but an unknown being. Besides, the power of corruption of the demons couldn't turn living beings into dragons but into mad creatures.