During the war, Guild used to lead the Exigency Programme, which is a group of highly trained individuals. The people did the dirty work such as assassinations and sabotage. Guild tried to recruit Ghastly and Skulduggery, but the two refused. Meritorious needed someone to assassinate Vanguard. Guild volounteered one of his men, telling him that he can disappear afterwards. Guild made all the evidence point to Mevolent's men, and Scarab in particular.
As Grand Mage
After the death of the Council of Elders, an emergency committee elected Guild to be the new Grand Mage. Though he had yet to elect his two Elders, he wanted to have Mr. Bliss as an Elder. Guild made his first appearance briefing Skulduggery and Valkyrie on the escape of Baron Vengeous.
Around this time, he wanted to place Tanith Low in jail for her involvement in freeing Moribund from his cell. However, Mr. Bliss convinced Guild that she wasn't in control of her actions.
Later, Skulduggery invaded the Irish Sanctuary, thinking that Guild was responsible for freeing Vengeous. When Skulduggery confronted Guild, he fired Skulduggery.
Guild recruited Davina Marr, an American mage, as the Sanctuary's newest detective. Guild had his fingers taken off by a vampire in the attack on the Sanctuary, but they were later re-attached. After his family was taken hostage, Dreylan Scarab tried to force Guild to blow up Croke Park Stadium, which would kill 80,000 people live on TV, with the Desolation Engine, which was designed to be armed only by Guild and to spare his life alone. Valkyrie and Skulduggery tried to stop him, but failed.
Just as he was about to blow up the stadium, Fletcher teleported him to the sea, where lots of fish were killed but he and Croke Park survived. Guild decided to finally accept the crime he committed, and was arrested. Marr lied to Skulduggery and Valkyrie saying that Guild wanted them to escort him to his cell. She wanted them to be there to be blown up in the Sanctuary with the other Desolation Engine.
Skulduggery flew away with Valkyrie and Guild, but one of Guild's legs was burnt off in the process.
He was old, short-tempered and cruel. His hatred of Skulduggery was such that he was happy when the latter was trapped in the Faceless Ones' universe and took credit for defeating the Gods. Despite his arrogant nature, he appeared to adore his wife and daughter.
Thurid was described as being in his sixties, with thinning grey hair, a lined face and cold eyes.