Vampire Destiny is the fourth and final trilogy in The Saga of Darren Shan by author Darren Shan. The trilogy included The Lake of Souls, Lord of the Shadows and Sons of Destiny. This series goes more in depth on the Lord of Shadows and the future where he rules, and Harkat's secrets of his past life are finally revealed.
Darren Shan along with allies Vancha March and Little People, Harkat Mulds, venture into the night to defeat the Vampaneze and end the war between the two. However, while one is defeated, the other shall become the Lord of the Shadows, the ruler of the dark who will destroy the world after the war. Darren must now help his friend Harkat find his true name and spirit in The Lake of Souls book. In Lord of the Shadows Darren returns to his hometown at the Cirque where he discovers his sister, who he hasn't seen in nearly two decades or more, and soon encounters the Vampaneze ending in a one last fight, which continues in Sons of Destiny where the final fight comes between Darren Shan and the Vampaneze lord, Steve, and as they are badly injured Darren kills Steve, and makes a dying Steve angry and Steve kills Darren so neither can live. However, Mr. Tiny resurrects Darren as a Little People in the final book of the Darren Shan series.
In the The Lake of Souls Darren embarks with Little Person, Harkat Mulds to find Harkat's true identity. They are forced to do difficult tasks, but they later find the truth in the Lake of Souls. He is later identified, at the end of the book that Harkat is Kurda Smahlt (a vampire traitor) who betrayed the clan to save the vampires and vampaneze from the War of Scars. Even though Harkat met Kurda, he still exists.
In the Lord of the Shadows Darren and Harkat return to Darren's hometown, in which Darren finds out that his sister, Annie, has grown up and has a kid. Meanwhile, Darren and Harkat meet a boy whose name is Darius. They take him around the Cirque Du Freak, and give him a free ticket. Tommy, Darren's friend from before he was a half vampire, is seen at Cirque Du Freak and is later killed at a soccer game. Darren is badly injured by R.V. and Morgan James, and is going through the purge. Later at the end of the book, Debbie, Darren, Harkat, Vancha, Alice, and Evra go after Morgan James and R.V. when Shancus is kidnapped by R.V. and Morgan, and kidnap Darius, who is revealed to be Steve's son (Mr. Tall is killed in the act, when Morgan James and R.V. come). Then they are lured to the old cinema theater in which they first went to the Cirque. There they meet Steve and work out a deal: Steve gives Shancus to Darren, and Darren gives Darius to Steve. However, Steve twists and breaks Shancus' neck, killing him. Steve, Morgan James, and the other vampaneze escape, but not before Steve reveals that Darius is Annie's son.
In the Sons of Destiny Darren goes to Annie's house and tells her about some parts of his vampire life. After much catching up, it is revealed that Annie had dated Steve and they had a baby, and Steve left them and never came back. Annie and Darius then flee to away from Darren, to avoid danger from Steve and the Vampaneze. However, before they do, Darren drinks the vampaneze blood in Darius (in the Lord of the Shadows, it is revealed that Steve blooded him) and they switch blood, making Darius a vampire, and Darren both vampire and a little vampaneze at the moment. Darren, Alice, Vancha, and Debbie go back to the Cirque Du Freak and an all out battle against the freaks and vampaneze begins. After a long duel, Darren kills Steve, and lets Steve kill him by angering Steve and saying "guess what Steve? I did want to be a vampire, and Mr. Crepsley turned me into one!". Later, Evanna the witch fishes Darren out of the Lake of Souls, and Mr. Tiny makes him a Little Person. Shortly thereafter Darren is to die. Mr. Tiny reveals that he is Darren and Steve's father, and tampered with time to make them go against each other to bring about the end of the world because he loves violence, and not much violence was going on with the humans. Mr. Tiny then sends Darren back in time, to the night where he and Steve first saw the Cirque Du Freak. There, Darren scares off young Darren from going to the balcony and discovering Steve wanting to be a vampire. It is told that the world will replace Darren and Steve with other people, as Darren never found out about Mr. Crepsley being a vampire and never kidnapped Madam Octa. Darren, before dying, gives Mr. Tall (who is still alive, due to them being back in time) his diaries for young Darren to read and "change the names, and turn the diaries into a book, that way "they" can know how it really happened."