PoV ???
'What is this feeling? What is that thing? A dragon this young should barely be able to talk; why is he eloquent?'
It's common knowledge that a dragon grows at a snail's pace. By the time they get to 150 years old, they finally gain self-awareness. It's at that age that they stop being just mindless monsters and start accumulating knowledge. The time may vary depending on the bloodline, but even for a noble dragon, he simply has too much experience fighting for his age.
Not only that, but he was slowly getting stronger the more he kept fighting us, to the point that every attempt at trapping him into an illusion has failed after the first one. He is also capable of constantly attacking two sides at once and is capable of applying his ability to just the body part I'm about to strike with extreme precision, as shown to me by the realm.