Magic is real, and the people who use it are dicks.
Wizards have been engaged in a bloody battle for supremacy for generations, and they don't care who they destroy in the process. In The Warrior Heir the wizards forge an uneasy alliance amongst themselves, and their combined power may be enough to destroy the haven of Trinity and all who have worked so hard to create it. The rebels' only chance to survive is to harness the power of the Dragon Stone. But the secrets of how to use the stone have been lost for centuries, and they're running out of time...
Sounds awesome, right? After all this build up, The Dragon Heir should be the apex of excitement and epic adventure! And yet--it's actually kinda boring. There are so many characters, and they all get more than their fair share of inner monologues about their personal problems. Even though this is the final battle, Chima introduces all manner of extraneous characters and extra plot points, then forgets about half of them. It's an unfocused mess of a book, and the climax is an unsatisfying deus-ex-machina.
The world building is subpar (I'm still bothered by the fact that we never see any hint that there's a broader world out there--it's all either western Europe or America. If both sides are in such dire straits, how come they never thought of seeking out help elsewhere?) and the plot is inconsistent. Chima isn't great at creating novel, memorable characters, either--I literally could not remember which male teen was which. That said, when Chima focuses on Seph, Jack or Madison, the story comes alive. And Chima is one of the few ya novelists who doesn't do gender essentialism. I loved that the male and female warriors are described using the same language (none of that half-hearted bullshit about how the dude is so strong and brawny and the lady is "lithe" or "slender"--they both hack people to death with swords and have got the incredible fore-arms to prove it). The characters have a wide range of motivations, abilities, and goals, irrespective of gender. It's sad how excited I am to find a fantasy book without that set of stereotypes.
Overall, I'd recommend this series, but with the caveat that the last book doesn't live up to what came before it.