Clace, bestowed with the mysterious and useless gift of the Holy Grail, is banished from the Winsland Earl family for being incompetent. Hinoka, whom he meets in a village, saves him from despair. Together, they become adventurers, gather companions, and rise to prominence as the S-rank party, Einheriar. While about to confess his feelings to Hinoka, fulfilling a childhood promise, Clace is rejected. Deep in the forest on a quest, they're nearly killed by their own party members. The hero, Rondo, reveals Hinoka's relationship with him and abandons Clace to monsters, leaving him to despair after being betrayed by his friends and lover. Betrayed, rejected, and left for dead, Clace desires power for the first time, awakening the Holy Grail's abilities. Vowing to trust no one, he seeks revenge. Though he's tasked with defeating the Demon Lord and receives pleas for help from the Elf Kingdom, his focus remains on revenge against those who betrayed him. His overwhelming power leads others to believe, "It's better if he's alone, isn't it?"