I'm looking for this series of books, teen to adult rating. It was about sentient dinosaurs that had evolved and changed, and lived in a medieval kingdom time.
It was based around three protagonists, with the leader being a raptor-based dinosaur whose people believed in thinking as fast as their speed. There was political turmoil, and they had to run past a lava river into a hidden forgotten valley sealed by magic, because that magic was feared. The valley held a lost kingdom that had a magic flute they had to play to gain entrance, with side effects. There are mechanical beasts made purely of magic and three sets of armour: blue, red, and green, I believe. It is also magic or enchanted. There was a moment in the first book where playing the flute paralysed the main character, and he had to focus himself inward and command his claws to release it to break free.
The second book is based around finding the lost fliers to join their war effort.