The Holy Knights journey into Merlin's old castle where they sense some form of shaking downstairs and went to find Diane, who travel there by the help of Oslo to their shock. Dreyfus walks toward Diane as the latter demand to get Elizabeth back which Dreyfus doesn't understand. Jericho rush toward Diane to kill her, but Diane used her Sacred TreasureGideon to smash the building around her.
After Diane destroyed half of Merlin's castle, the Holy Knights got out unscathed and comments on the Serpent's Sin of Envy's power drawn out by her Sacred Treasure. Gilthunder initiated the battle by using his Thunderbolt to cast Purge of the Thunder Emperor on Diane, electrocuting the giant in the process. Howzer seemed hesitant at first but when Dreyfus asks if he's holding back because of Diane, Howzer gave in with a war cry and used Tempest to perform Rising Tornado. These two powers combine into Combined Technique: Dragon Castle, sending Diane into the air while being electroshocked. Helbram used his Link to call upon his subordinate Gustaf to lend his Ice Fang power and cast Hail Bullet upon Diane, injuring her. But the Serpent's Sin of Envy retaliated by impaling Helbram with Ground Gladius seemingly killed in the process, while the same time freeing herself from Gilthunder's and Howzer's combined technique.
As Diane lands on the ground before Dreyfus, the giant attempted to impale him with Ground Gladius again only for the Great Holy Knight to shatter her technique much to her shock. Dreyfus then explains the nature of their magical abilities and reveals his power Break as he declares that he'll shatter dreams and ideals, and crush those who stands in his way of supremacy. As Diane attempts to swing her Gideon to smash Dreyfus, she was struck in the chest by the Great Holy Knight's Pierce and falls defeated.