WARNING: The following contains spoilers for Black Clover Vol. 23, by Yuki Tabata, Taylor Engel and Annaliese Christman, available in English now from Viz Media.
Volume 23 of Black Clover starts off with the conclusion of Asta and Nero’s trial at the Royal House of Kira and ends by setting the stage for the highly-anticipated war between devils and wizards. The Clover Kingdom needs a scapegoat, after all, and who better than the mysterious devil host himself? But the royals will not acknowledge the assistance of a devil and demand that Asta receives the punishment of death. Regardless of his ability to control the power of the devil, Asta is only seen as a grotesque being, but luckily for him, the Black Bull have his back, making a grand entrance to rescue their capture comrades in the latest translated volume of the manga.
The sense of team comradery is heavily displayed here, especially after the heart-warming speech Yami gives to Nero, which explains how she is now one of the Black Bulls. But while they are willing to sacrifice themselves for the safety of their comrade, Fuegoleon and Nozel arrive right before things get really heated. They deliver an order from King Julius, stating that Asta will be exiled from the Clover Kingdom; in the meantime, though, he will be responsible for researching the mysteries of the devils and curses. He must report back with credible information to absolve him of any crimes and clear the name of the Black Bulls. Not realizing the seriousness of his condition, Asta and the Black Bulls embark on their new mission.
While the middle chapters following this are more like filler, they still prove to be informative for the Black Bulls, and give a better insight into the overall story. First, Charlotte is approached by Yami because he wants to ask her about the curse that she's been afflicted with, but she gets flustered in typical Charlotte fashion and avoids him at all costs.
The encounter causes her to admit to her brigade that she likes Yami, and instead of receiving backlash, to her surprise, they support her decision -- even offering her some dating advice. The secret to her curse mark doesn’t get fully revealed but she does finally get to go on a date with Yami. In the meantime, other Black Bull members seek advice from Gordon’s family about curses. Needless to say, they don’t learn much about but they do discover that the Heart Kingdom is housing a devil as well.
While looking for clues, Noelle finds out that her mother was killed by a curse inflicted by the devil known as Megicula. The curse is so deadly that anyone who speaks of it also gets cursed, which is why her brother never mentioned it. Noelle tracks down Dorothy, Captain of the Coral Peacocks, because she knows about the incident with her mother and Megicula. In order to discuss the matter, Dorothy uses her dream magic to transport them into the Glamour world -- a dimension outside of the real world. All signs lead to the Heart Kingdom but, as Boromir might say, one cannot simply walk up to the kingdom and expect to be welcomed with open arms.
Noelle reaches out to her cousin Mimosa who informs her of an exchange program between royals that swaps wizards from other kingdoms in order for them to learn new tactics and expand alliances. They decide to take that route, and Asta, Noelle, Mimosa, Finral and Nero embark on their journey to the Heart Kingdom. When they reach the border of the Heart Kingdom, they are greeted by the guardian Gaja. They notice that the Heart Kingdom’s mana feels different from the Clover Kingdom’s, and Gaja informs them that the wizards of the Heart Kingdom use the natural mana around them to fuel their magic. He also explains how the princess of the Heart Kingdom is able to manipulate the water elements that make up the kingdom, and how she uses that to monitor everything going on at all times.
In an unfortunate series of events, Asta is encapsulated in a large water dome while Gaja attacks the other young wizards. In their desperate attempts to rescues Asta, the group discovers how powerful Gaja truly is. While the others are fighting Gaja, Asta comes face-to-face with the Princess of the Heart Kingdom. The battle seems fierce at first, but the Princess turns out to be a clumsy, unmannered royal by the name of Lolopechka. Her Water Spirit, Undine, is very apologetic for Lolopechka’s clumsiness. Undine’s relationship with Lolopechka is almost like that of a caretaker -- she may be the one guiding the young princess down the path of royalty. The battle with Gaja concludes after the Black Bulls and Mimosa prove to be a stronger threat than he anticipated. Gaja admits to only be testing their strength, leading the others to the princess.
Lolopechka immediately reveals that she too has been cursed by Megicula, and only has about a year to live. The reason they accepted the invitation from the Clover Kingdom is to make an alliance with strong wizards to infiltrate the Spade Kingdom and defeat Megicula. As details about the mission are being explained, Luck, Magna and Vanessa investigate the Diamond Kingdom. To their surprise, they witness a member of the Spade Kingdom standing over the corpses of many fallen Diamond Kingdom wizards. The more alarming part is when Luck admits to not wanting to fight the mysterious foe, meaning that the enemy is far more powerful than they imagined.
In the Heart Kingdom, wizards are rated based on “Stages,” wherein the lower the number, the stronger the wizard. In Asta’s case, they refer to him as an Arcane Stage. The Heart Kingdom is interested in the variety of unnatural magic the Clover Kingdom possesses and hopes to add that to its arsenal. Since the situation has now gotten dire, the Kingdom reaches out to King Julius, and with his blessing, the young wizards agree to train in the Heart Kingdom for the next six months to prepare for the battle against the devils.
Volume 23 of Black Clover ends with a fast-forward over those next six months, finishing with Yuno floating over the Clover Kingdom, looking as determined as ever.