Since this cards second effect can be triggered in either turn, and is a Quick Effect, use it to quickly rid the field of a potentially annoying or threatening card (such as "Number 11: Big Eye", and "Number 101: Silent Honor ARK"). That way, you can effectively ruin a strategy before it can start, as well as get around troubling cards before they can become a threat.
Select this card with "Last Turn" while you already control either "Sangan" or "Witch of the Black Forest", adding a Monster with 1500 ATK or DEF to your hand. After your opponent Special Summons their Monster, use this card's effect to send your new Monster to the Graveyard, and destroy your opponent's. If this results in you being the lone player with a Monster during the End Phase, you win the Duel.