Warning: The following contains SPOILERS for the first three episodes of Young Justice season 4, part 2.
The first three episodes of the second half of Young Justice season 4 introduced a number of characters connected to Aquaman and DC Comics' version of Atlantis into the reality of Earth-16. Some of these characters are making their first animated appearance, though they did have cameos in the comic books based upon the Young Justice series. Some of these characters are also obscure, as is often the case with minor character cameos in Young Justice.
The fourth major story arc of Young Justice season 4 centers around Kaldur'ahm, who started the series as Aqualad, but grew into the role of Aquaman, replacing his mentor on the Justice League. The events of the first three episodes overlap with the previous arc focused upon Zatanna, as we see the effects of the Chaos Lord Child's attacks on Earth from another perspective. This culminates in an epic action sequence in which the heroes of Atlantis must protect their home from a flesh-consuming wave of red water.
Related: What To Expect From Young Justice Season 4, Part 2
Despite this intense action, the episodes are largely set against the backdrop of a peace conference between the various Atlantean kingdoms and the focus is on the political problems of Atlantis. This leads to the introduction of many characters taken from the world of DC Comics. While most of them have a connection to Aquaman, there are others who were only tied into the same undersea world as Orin and Mera later.
Much of the plot of the Young Justice season 4 part 2's premiere centers around an Atlantean prophecy, similar to the legend of King Arthur, regarding the rise of a true king of Atlantis and a
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