Lord Loss is the first novel in the fictional Demonata series book by best-selling teenage horror author Darren Shan. It was originally published in the UK on 6 June 2005. Soon after, it appeared in Japan and America, where Shan's previous series, The Saga of Darren Shan, had sold millions. The novel is set in Ireland and is told in present tense first person through Grubbs Grady, a child whose family are all chess players.
Grubitsch "Grubbs" Grady, the younger child of chess-obsessed parents, grows increasingly uneasy with the recent strange, nervous behaviour of his parents and sister. One night, he finds the mutilated bodies of his family and encounters Lord Loss, a gruesome human-like demon who sets his two familiars, Vein and Artery, on Grubbs.
Although Grubbs manages to escape, he is deeply traumatised and is placed in a mental institute. He refuses to respond to treatment until he is visited by his father's younger brother, Dervish Grady, who tells Grubbs that he knows demons exist and convinces Grubbs to finally accept help.