WARNING: This article contains spoilers for Black Clover Chapter #279, “The Door To Hell,” by Yuki Tabata, Taylor Engel and Annaliese "Ace" Christman, available now in English from Viz Media.
In Black Clover Chapter #279, “The Door To Hell,” the Clover Kingdom's Magic Knights have failed, and now their greatest fears have come to fruition: the arrival of the devils.
The one key player Nacht didn’t anticipate was the magic scholar, Morris, from the Diamond Kingdom. Morris has now acquired the ability of a devil host, and with his new profound skill, he was able to extract special knowledge from Lolopechka to accelerate the ritual of Qliphoth. With the arrival of two new devils, the tone quickly shifts, and their hostility towards the humans, and possibly devil hosts, is palpable.
In Chapter #279, the Dark Triad have succeeded in their ultimate plan, but don’t realize that the true puppeteers are taking over the show now. Upon their arrival, Nacht is hit with a wave of desperation, something not seen from him in the series thus far. What's especially interesting is that not only does Dante look surprised that the devils have arrived so soon, but even he looks terrified by their entrance.
The devils waste no time and attack Jack and Nacht without lifting a finger. Their strength is monumental compared to the Magic Knights, and after they’re done with the Clover Kingdom, who will they focus their attention on? In the most extreme case, the Dark Triad will be overpowered by the devils, since the original bodies of the hosts will be able to enter the human world, and the devils won't have use for any human mages.
Each of the Dark Triad was used for this solemn moment, but taking advantage of Morris’s blindness and desire for magical knowledge proved to be the key to the ritual's success. It took the culmination of various types of magic to open the gate for the devils to enter the human world. There is some foreshadowing in that detail alone, and is potentially setting up a team-up between all the kingdoms against the devils.
At this point, the arrival of the devils is not advantageous for the Spade Kingdom, particularly the Dark Triad. The devils are arrogant, and their abilities potential alone is devastating. Dante’s expression says it all, as he looks at them with shock, realizing that he doesn’t have nearly enough magical power to handle them. With the arrival of the first two devils, the plan to eliminate the mages is only beginning.
Nacht’s expression also validates the devil’s strength, as he moves to swiftly squash the current situation in the Black Clover manga. Yami and Vengeance are still being used for the ritual of Qliphoth, and now Nacht has to deal with two high-ranking devils. It’s still unclear if each of the other teams is also dealing with a pair of devils, but based on the reaction everyone had to the release of the dark roots from the ritual, it’s safe to assume the other mages will eventually encounter them.
At this point, no Kingdom is safe from the devils' threat, but Asta and Liebe will likely be the "x" factors that turn the tides.