The Witch & The Samurai W&S

Long ago, before humans existed on this planet, negative energy was present for an unknown reason. Witches consumed this negative energy to survive. One day, a group of warriors known as samurai were formed to fight the witches. Namida Mirai was a boy who never desired to become a samurai, but destiny chose him to be a great one. Day after day, battle after battle, he met a powerful witch named Aisuru Kirai. She warned him that once he eradicates the witches, the world will end. What can Namida Mirai do? Is Aisuru lying or telling the truth