The Truth of DOOM

The duel between Yugi and Raphael continues. Raphael’s LP is 4000 and Yugi 3000. Yugi attacks the Guardian Guraru (ATK 3000) with the special ability of the Five Star Brothers Kuriboh. He also fuses Black Magician Girl with Timaeus to create Dragon Knight Black Magician Girl. It appears to have a special effect, discard the hand to the graveyard and changing its ATK to 0 will destroy the opponent’s monster. Will Yugi’s counterattack succeed? And what is DOOM’s trying to accomplish?