Artemis and Kaldur know (or at least, Kaldur did know) how to defeat Black Beetle - and possibly the Reach. Maybe they’re not conscious of it yet (if Kaldur is conscious at all), but they know a way to beat him.
No, I mean the answer is literally sorcery. In “Darkest”, Kaldur takes down Blue Beetle with his sorcery - and he’s surprised about it, and even states “I was not sure that would work.” Assuming that the sorcery affected the scarab and not actually Jaime, then Black Beetle should be susceptible to it too.
Here’s hoping that Artemis can remember this in time (or Aqualad is able remember anything in time) and they are able to use this when it come to defeating Black Beetle
Oh my god I’m so happy you brought this up, because the reason (in Jaime’s first Blue Beetle comic - DCnU, what DCnU) that the Scarab didn’t take over Jaime (or anybody else) properly, was that it had been exposed to magic on Earth and this sort of fried its circuitry.
Which meant that Jaime was able to stay in control and eventually subvert the Scarab (free will! whoo!).
I have no idea. How this will play out in Young Justice, or even if any of it is still applicable.
Further reason they need Traci to be one of the pod kids.