If this face-up card is destroyed by battle, or leaves the field because of an opponent's card effect while its owner controls it: You can add 1 Level 7 WATER monster from your Deck to your hand
It gets sent to the graveyard during the end phase of the following turn, but that part is considerably less relevant considering its likely to be taken to use to make another monster
Those cards will either negate or delay your opponent's power moves
The best Infernoids are, in order: 1
While this card is in your hand or GY, if a face-up Dragon monster on the field, except "Keeper of the Shrine", is sent to the GY by a card effect or because it was destroyed by battle: You can Special Summon this card, then, if that monster sent to the GY is a Normal Monster, you can add 1 Dragon Normal Monster from your GY to your hand