1 Tuner + 1+ non-Tuner Fiend monsters
During your opponent's Main Phase (Quick Effect): You can target 1 Effect Monster on the field; discard 1 monster, and if you do, negate that monster's effect until the end of this turn. You can only use this effect of "Groza, Tyrant of Thunder" once per turn. If a Fiend monster(s) is sent from the hand to your GY (except during the Damage Step): You can apply 1 of the following effects to this card, until the end of this turn.
• Cannot be destroyed by battle. • Cannot be destroyed by your opponent's card effects. • Your opponent cannot target this card with card effects.