He is addicted to Warpstone which seems to fuel his megalomaniac paranoia. His plans and schemes are far reaching and frequently involve humans, a subject that Thanquol considers himself somewhat of an expert. Over the years he has been sent on many missions by the Council of Thirteen all across the Under-Empire from the frozen Chaos Wastes to Far Cathay and has become one of their favoured agents.
Examples of his work were the bribing of the head of the Secret Police of Elector Countess Emmanuelle von Liebewitz, the nearly successful invasion of the city of Nuln, the attack on the camp of the Dwarven Slayer engineer Malakai Makaisson when trying to steal his Airship, an attack on the fortified mansion of Ulrika Magdova's father in the steppes of Kislev to kidnap the girl to use her as a hostage, and so on. Most of his recent plans were destroyed by the heroes Gotrek & Felix and he loathes and fears them in equal measure.
After one failure too many, Thanquol was banished by the Council of Thirteen to an outpost in the backwaters of Estalia, where he discovered his two greatest nemeses were still alive, 20 years after his last encounter with them.
In the novel Elfslayer, he manages to capture the pair and plans to torture them to death in recompense for all they have done to him, but after a High Elf prisoner mentions they were trying to recover a Dark Elf weapon known as the 'Harp of Ruin', Thanquol released them and allowed the Druchii to capture them, hoping they will cause enough destruction for him to steal it. The plan worked at first, in that Thanquol's agents were able to steal the harp, but failed in that Gotrek destroyed the Harp, killed most of the Dark Elves and Skaven trying to recover it, and came incredibly close to killing Thanquol himself: though the Grey Seer survived, he lost his right hand to Gotrek's axe, and has vowed to take revenge for the injury. Likewise, Felix and Gotrek have vowed to kill him the next time they meet, on account of the fact Thanquol's minions tortured Felix's father, Gustav, to death while trying to gain information on the pair's whereabouts.
Thanquol is also known to have attempted to use ancient Elf stones to destroy the lands of men, a scheme which was thwarted by Commander Morgan Bernhardt and his army. He also once tried to summon a Verminlord of the Horned Rat to aid an underground assault on Karak Kadrin, but this plan failed spectacularly when he instead managed to summon Skarbrand, a Bloodthirster of Khorne, who swiftly annihilated the Skaven army before fading away. As is expected, the only survivor of this slaughter was Thanquol, who fled to safety at the first sign of trouble.
There have so far been three Rat Ogre bodyguards of Thanquol, each called Boneripper. The first was slain by Gotrek Gurnisson in Nuln. The second was a mutant with an extra arm. This one too was slain, this time by Felix Jaegar, who tricked it into swallowing a grenade.
Recently, Clan Skryre gave Thanquol an important gift as a sign of reconciliation for past deeds. Clan Eshin warriors were hired to recover the body of Thanquol's first Rat Ogre, which had been on display in a freak show in Nuln. Clan Skyre reassembled the cadaver and reanimated it as a mindless machine at the order of Thanquol.