Any spells directed at Be'lakor will be Miscast on the roll of any double (if a spell is cast at him with Irresistible Force, it will be cast with Irresistible Force, then the wizard will suffer an immediate Miscast).
Source: Warhammer Fantasy: 6th Edition
Any spells directed at Be'lakor will be Miscast on the roll of any double (if a spell is cast at him with Irresistible Force, it will be cast with Irresistible Force, then the wizard will suffer an immediate Miscast).