Question: Hydra is an album by Within Temptation and contains guest appearances by an American metalcore vocalist best known for being the vocalist of what two bands?
{'answer': 'Killswitch Engage and Blood Has Been Shed', 'supporting_facts': [['Hydra (Within Temptation album)', 0], ['Hydra (Within Temptation album)', 2], ['Howard Jones (American musician)', 0]]}