First published in 1992, Dragon War is Laurence Yep's final installment in the Dragon Series. It is the sequel to Dragon of the Lost Sea, Dragon Steel and Dragon Cauldron.The Boneless King manages to capture Shimmer, Monkey and Indigo, and steal Baldy's Cauldron. The events of the book are mostly about their attempts to get it back, while preparing troops for a mounting war between the humans and the dragons.
- A Child Shall Lead Them: In the book's final chapter, it's revealed that Thorn is the only living heir to the throne.
- Adipose Rex: King Sambar, who has had over a century of peace and feasting to expand his waistline.
- And I Must Scream: Thorn, whose soul is trapped inside Baldy's Cauldron.
- Conservation of Ninjutsu: When the trio are vastly outnumbered by the Boneless King's "perfect" stone soldier army, they easily smash them all to bits without sustaining any damage at all.
- The Dragon: Pomfret, who becomes the Boneless King's right hand man, and has a vicious fight with Shimmer in the climax of the novel.
- Foreign Queasine: The contents of the High King of Dragons' larder is filled with all sorts of creepy-crawly undersea creatures. They're so exotic and frightening-looking that the dragons unleash the (harmless) creatures upon human soldiers and bluff about how poisonous and deadly they are to scare them off.
- Heel–Face Turn:
- Living Forever Is Awesome: The Snail Woman and The Smith's limited magic can only reanimate Thorn in a humanoid shape, not restore him to a human body. They point out that this is actually a pretty sweet deal for everyone because doing so means that Thorn is effectively immortal. Immortal kings don't have to pass on their throne to unworthy and corrupt heirs. Nor do they have to worry about assassination.
- Magic Mirror: The World Mirror, which shows possible futures.
- Master of Illusion: Although Shimmer had mostly been using the dream pearl to perform transformation magic for the past three books, she really demonstrates why it's called the dream pearl in this one.
- Obfuscating Stupidity: The Boneless King, who had taken over The Butcher's body, has to pretend to be a Muggle and conceal his magical ability behind spells of another mage in order to fool everyone into thinking he's still The Butcher.
- Omnicidal Maniac: The Boneless King.
- Our Gargoyles Rock: The Boneless King has an army of "perfect" rock soldiers.
- Redemption Equals Death: When Pomfret discovers the Boneless King's actual plans for the future, he makes a final redemptive sacrifices to defeat the Boneless King.
- Royals Who Actually Do Something: King Sambar... finally.
- Unskilled, but Strong: Shimmer, it turns out, who can transform anything (including herself), and perform impossibly realistic and dazzling illusions with the dream pearl, cannot cast a spell to save her life without it.