Thanquol is a Grey Seer and therefore a Level 4 Wizard who uses spells from the Skaven Spells of Ruin and/or the Skaven Spells of Plague in any combination, and may choose to substitute any one of his spells for The Dreaded Thirteenth Spell.
Source: Warhammer Fantasy: 8th Edition
Thanquol is a Grey Seer and therefore a Level 4 Wizard who uses spells from the Skaven Spells of Ruin and/or the Skaven Spells of Plague in any combination, and may choose to substitute any one of his spells for The Dreaded Thirteenth Spell.