The Guardians are immune to all CC (including Shackles) in both normal and heroic Naxxramas. The tactics for dealing with the Guardians on normal difficulty are: * Second tank with dedicated healer tanks the Guardians away from the raid while the main tank and all DPS focus on Kel'Thuzad. The Guardians have too much HP to attempt to kill at the same time, so in order to prevent a wipe, all DPS remains on Kel'Thuzad until he is killed (and it's recommended you do it quickly, as the stacking self-buff can become problematic over time). * Main tank holds both Kel'Thuzad and the Guardians, with all DPS remaining on Kel'Thuzad until he is killed.