Rulings powered by The Netrep API. If you Tribute Summon 'Thestalos the Firestorm Monarch' successfully, and your opponent discards a monster like 'Oustanding Dog Marron' or 'Regenerating Mummy', you still inflict damage because the monster was discarded to the Graveyard (even though it doesn't remain there). If 'Banisher of the Light' is face-up on the field, no damage is inflicted because the card is not discarded to the Graveyard. This card's effect always activates when Tribute Summoned, even if your opponent has no cards in their hand. [Re: Gemini Imps] If your opponent Tribute Summons 'Thestalos the Firestorm Monarch', you can chain with the effect of 'Gemini Imps'. The effect of 'Thestalos the Firestorm Monarch' would be negated and it would be destroyed, and then you would draw a card.
Dark Revelations 3
When this card is Tribute Summoned, randomly discard 1 card from your opponent's hand to the Graveyard. If the discarded card was a Monster Card, inflict damage to your opponent equal to the Level of the monster x 100.
Thestalos the Firestorm Monarch