Episode 51

Proof of Rightness (正しさの証明) is the 51st Page of Yūki Tabata's Black Clover and the final episode of the first season.

Summary
Asta congratulates everyone on a job well done back at the Black Bull base. They remember suddenly that they forgot Gordon Agrippa, who is sitting in a corner upset. Yami Sukehiro tells the squad that he is going to go report to Julius Novachrono. He says that Charmy Pappitson is going with them so that she can bring along the prisoners and Finral Roulacase will transport them there. Asta also asks if he can come but Noelle Silva reprimands him and tells him that he needs to rest. Yami agrees that he should stay but since he was there when the Magic Emperor gave them the mission, Yami allows him to come with them.

They arrive at the Royal Capital and Yami dismisses Finral allowing him to go flirt with cute girls. In his office, Julius tells the Black Bulls that he sent Vetto's corpse for an autopsy and will interrogate the other prisoners that they brought back. Julius praises Charmy for her Restraining Magic and Yami hands over the magic stone. Julius praises them for accomplishing this mission and also points out that Yami has gotten stronger because of it.

Julius remembers when he first appointed Yami as a Magic Knight captain and tells him that he has become a magnificent captain. Yami responds that he has just proved that Julius was right and that his Magic Knights proved that Yami was right. Julius congratulates Asta on his newest achievement and tells him that he is one step closer to becoming the Magic Emperor. Asta asks him if he can have his autograph and Yami gets mad at him.

Suddenly, Marx Francois interrupts their meeting and tells Julius that Kiten is under attack by a Diamond Kingdom army. Marx shows them a visual and Asta asks why there are so many people attacking. The group is being led by Ragus, Broccos, and Yagos, three of the Eight Shining Generals. Asta asks what that is and Yami explains that they are the eight strongest of the Diamond Kingdom.

The generals say that if they conquer Kiten, it will give their forces an advantage and resources. A group of Purple Orca form a defensive line atop Kiten's wall to prevent army from invading. They activate the magical barrier and focus their attacks on Ragus in order to take him out first. Ragus' subordinates protect him with a barrier, and Ragus retaliates with his Thunderbird Cavalry: Sky-Splitting Magic Bow Armament, which pierces and brings down Kiten's barrier. The army charges ahead and enters the town.

All hope seems lost as Yami, Asta, Marx, and Julius watch from a distance. Suddenly, several Golden Dawns arrive ready to turn the tide of the battle. Yuno attacks Broccos and blows him away. Sylph tells Yuno to use her magic and that he does not make friends because he never smiles. Sylph tells him to hurry up and defeat these guys so that they can go on a date. Yuno refuses, much to Sylph's dismay. Julius marvels at the wind spirit and wants to meet her in person. Charmy is excited to see her meal-saving prince, while Asta just grins. Julius tells them that he would like to send reinforcements to help. Yami asks if he wants them to go but Julius asks if he is sure since they just returned from the Seabed Temple. Yami says that he feels invincible and that he is concerned about someone there. Julius says that he would like to go but he cannot leave the capital. Yami wishes he had brought Finral to the office so that they could head over to Kiten. Asta asks if he can go but Yami tells him he will just get in the way because he is injured. Charmy promises to protect Asta. Yami relents and tells them that they can come. The three of them go in search of Finral.

Meanwhile, William Vangeance and Langris Vaude watch the battle. They decide to make the Diamond Kingdom regret stepping foot in their country.

Events

 * Invasion of Kiten

Petit Clover
Promise! (約束!): Asta and Yuno sit at a bar and reflect on their promise to become the Magic Emperor, but Yuno acts too cool and forgets his own identity.