Kingdom of Ash (2018) is the final novel in Throne of Glass, a new-adult fantasy series by Sarah J. Maas. The Kingdom of Ash follows The Assassin’s Blade (2014), Throne of Glass (2012), Crown of Midnight (2013), Heir of Fire (2014), Queen of Shadows (2015), Empire of Storms (2016), and Tower of Dawn (2017). Told from multiple third-person points-of-view, the series follows protagonist Aelin and her allies as they prepare for a war to defeat the parasitic demons called Valg intent on conquering their world.

Throne of Glass is Sarah J. Maas’s debut series, followed by her other New York Times bestselling series, A Court of Thorns and Roses (2015) and Crescent City (2020). Her books have been translated into over 38 languages worldwide.

This guide refers to the rereleased hardback edition published by Bloomsbury USA in 2023.

Content Warning: The source material features graphic depictions of violence, torture, and war.

Plot Summary

Kingdom of Ash takes place on the continents of Erilea, the Southern Continent, and a continent comprised of the kingdoms of Doranelle and Wendlyn. The world has been infested by parasitic demons called the Valg—invaders from another dimension that possess people. Battling the demons are the allies of Aelin Galathynius, the heir to the throne of Terrasen. Aelin’s forces include different species of sapient residents of her world: humans, Fae, shapeshifters, and witches. A powerful magic user who wields fire, Aelin poses a particular threat to the Valg, who are more vulnerable to fire than to other weapons. Both Aelin and the Valg are seeking magical Wyrdkeys, artifacts that open the Wyrdgate portals that could send the Valg back to their dimension for good or empower the wielder to take over the world. In the previous two novels of the series, which take place simultaneously, Aelin’s allies split into two groups: Aelin led a contingent to gather remaining Terrasen forces and learned that the Valg are led not only by the ancient King Erawan but also by Queen Maeve, who has been disguised as Fae for millennia; while Chaol went south to heal grievous injuries and recruit the inhabitants of the Southern Continent to join Aelin’s side.

The novel opens two months after the events of Empire of Storms (2016), and Tower of Dawn (2017). It has been two months since Aelin and Fenrys were taken captive by Maeve. They endure daily torture while Elide, Lorcan, Gavriel, and Aelin’s mate Rowan search for them. Fenrys, Gavriel, Lorcan, and Rowan were once part of Maeve’s elite Cadre of Fae warriors. Now released from their blood oaths to her, Lorcan, Gavriel, and Rowan are free to help the Terrasen noble Elide hunt down and torture Maeve’s remaining commanders for information. Their search leads them away from the kingdom of Doranelle despite Elide’s belief that Aelin and Fenrys are somewhere inside the city.

Aelin is tortured by Maeve’s sadistic warrior, Cairn. Fenrys is forced to watch while Maeve kills Fenrys’s twin, Connall. Afterward, when she is stuffed back inside the iron coffin that contains her powers, Aelin hammers on it enough to dent it, sending a surge through the mating bond to Rowan. This magical surge proves to Rowan that Aelin is in Doranelle, so he and his companions return to rescue their imprisoned allies.

Maeve transfers Aelin to a secure war camp outside Doranelle while she travels to find a Wyrdstone collar—a magical artifact that binds its wearer and enables Valg possession. With Maeve gone, Fenrys severs his blood oath to Maeve. Elide and the Cadre locate Aelin and Fenrys and aid their escape, killing Cairn in the process. Fenrys’s life is in danger from the termination of the blood oath; Aelin saves him by offering him a blood oath to her instead. She now has three warriors thus sworn to her: Rowan, Fenrys, and Aelin’s cousin Aedion. Aelin, Elide, and the reunited Cadre travel through the hidden caves to the coast, where they set sail toward the kingdom of Terrasen on the continent of Erilea. Before they reach land, Aelin also offers Lorcan the blood oath to confirm she can trust him.

Meanwhile, Aelin’s many allies—the Whitethorns of Doranelle, Galan Ashryver’s forces from Wendlyn, Ansel of Briarcliff’s armies from the Western Wastes, the Silent Assassins of the Red Desert, and the Bane legion led by Aedion—gather to defend Terrasen from Erawan’s forces. Lysandra impersonates Aelin during her absence to keep their allies from deserting. However, the ruse soon fails: When a Valg attacks Lysandra, he discovers her true identity and sends word to Erawan that Aelin is not with her forces. Erawan attacks Terrasen at once. When all hope seems lost, the pirate Captain Rolfe arrives with his legendary Mycenian fleet. They manage to surprise and temporarily delay Erawan’s forces until Aedion and his armies can retreat to Orynth, Terrasen’s capital city.

Chaol is unaware of Aelin’s captivity as he sails for Erilea with his pregnant wife Yrene, the healers of the Torre Cesme, and the khaganate’s armies—residents of the Southern Continent that have agreed to ally against the Valg. With them are: Nesryn Faliq, an Adarlan rebel and Chaol’s ex-girlfriend; Sartaq, the heir to the khaganate throne; and Falkan Ennar, a shapeshifter. On the way, they discover part of Erawan’s army heading for the Adarlan city of Anielle—Chaol’s home. They change course, heading to defend Anielle.

After several days of battle, Aelin, Elide, and the Cadre make landfall and make for Anielle. The two groups find each other. Chaol informs Aelin that Maeve is Valg and that Torre Cesme healers are capable of vanquishing Valg from hosts without killing the hosts in the process. Aelin and her comrades help Chaol defend the city. When the massive dam breaks, Aelin uses all her power to evaporate the water before it drowns the Southern Continent’s army. As a gesture of gratitude, the khaganate agrees to march north to Terrasen with Aelin.

Dorian, now King of Adarlan, joins the witch Manon and the Thirteen—Manon’s loyal witch wyvern riders—in the search for the Crochan witches and the final Wyrdkey. The former rulers of witch society, the Crochan witches value peace; they have long been hunted by the Ironteeth witches who deposed them. Manon, the former heir apparent of the Ironteeth clan who rebelled against their vicious order, recently learned that she is Crochan herself. Slowly earning the Crochan clan’s respect, Manon sends word to another potential Ironteeth ally: Petrah Blueblood. When the Crochan camp is attacked by the three Ironteeth Matrons, Manon fights all three at once. She kills the Yellowlegs matron but allows Petrah’s mother to live as a gesture of goodwill. Manon’s grandmother, the Blackbeak Matron, flees. Afterward, Manon is gifted the Crochan crown. She arrives at Orynth with 5,000 Crochan witches, just in time to prevent the defeat of Aedion’s forces. Petrah Blueblood’s Ironteeth legions arrive shortly. The Thirteen sacrifice their lives to destroy Erawan’s last witch tower, capable of leveling the city.

Dorian studies a stygian spider—a sapient species under the command of Maeve. He learns its shapeshifting powers, kills it, and infiltrates Morath, an Adarlan city controlled by Erawan. While there, he discovers Maeve has allied with Erawan. After securing the third Wyrdkey, Dorian weakens Morath’s foundations and collapses the entire stronghold on Erawan’s backup forces. On his journey north, Dorian crosses paths with Aelin and Chaol. After she tells him about her vision of how to defeat the Valg for good, Dorian and Aelin decide to forge the magical Lock. This artifact will allow them to permanently close the Wyrdgates so Erawan won’t be able to bring his brothers back into their world. Aelin and Dorian give up most of their power to do so, but Aelin shoves Dorian out of the liminal realm at the last minute, so that only she must sacrifice her life for the task. However, when she confronts the gods, they refuse to rid the world of Erawan as they’ve promised. All Mala Fire-Bringer, the goddess that is Aelin’s distant ancestor, is willing to do is give Aelin some magic back. When Aelin returns, she reveals that she only survived forging the Lock because she gave up her mortality and most of her magic.

Aelin, Chaol, Dorian, Elide, and the Cadre join the rest of their allies and armies in Orynth for the final battle, where Maeve and Erawan make their first battlefield appearance. Gavriel dies protecting Aedion and the Bane soldiers. Aelin and the remaining Cadre distract and kill Maeve while Yrene uses her healing magic to destroy Erawan.

Yrene’s name is chanted as the cry of victory when all of Erawan’s remaining Valg forces crumble. After the war, Falkan Ennar reveals that he is Lysandra’s uncle; she eagerly accepts him into the family she’s formed with Aedion and her adoptive daughter Evangeline. Elide and Lorcan marry and make a home in Perranth. Aelin becomes Queen of Terrasen; at her coronation, she offers Aedion the ceremonial blood oath. Yrene and Chaol decide to live in Adarlan; Yrene plans to start a Torre Cesme healing center in Erilea. Queen Ansel of Briarcliff agrees to share the Western Wastes with Manon, allowing witches to return to their former Witch Kingdom. Dorian and Manon leave their relationship open, but he enlists her help in training the wyverns Erawan left behind as Adarlan’s new aerial legion. Nesryn Faliq returns with the khaganate to the Southern Continent, where she plans to marry Sartaq and become Empress.

Aelin and her kingdom spend months rebuilding, and when spring comes, kingsflame—a rare flower symbolizing peace—blooms across Terrasen.