Terrible Young Justice Headcanon Theory
Nightwing planned for, or at the very least anticipated, someone on his team being angry enough to take Kaldur out.
That's why Artemis was sent in as a second undercover operative, instead of just going into hiding after her "death". She's a back-up double agent.
Terrible theory entertained by my brain for two reasons:
1. Kaldur being deep undercover was dangerous enough. With two agents that's double the risk of possibly being discovered. Even only one of them getting their cover blown casts immediate suspicion on the other. If Kaldur is caught, the Light will side-eye "Tigress" unless she can somehow convince them she had nothing to do with Kaldur's subterfuge. If Artemis is caught, Kaldur loses the trust he's worked so hard to gain from the Light. Why take such a risk when it'd be easier to send Artemis into hiding? Because if one of them is accidentally killed on the job, they still have an agent on the inside.
2. Nightwing's lack of a response to hearing that M'gann had a confrontation with Kaldur. (That has left her visibly shaken and catatonic.) Even without knowing about her mindwiping habit, shouldn't he have been at least a little bit concerned about the possibility of her taking revenge on Kaldur in general? I mean, it's not like he doesn't know that the Team is seriously out for Kaldur's blood. It's not like he didn't know their rescue mission contained the risk of someone running into Kaldur and possibly attacking him. Yet we get absolutely zero reactions from his end. No reaction shot. No offscreen questions asking for clarification. We just cut to him calling the Watchtower with his information. Why are you not more concerned about the fact that one of your teammates, all of whom are still seriously distraught and grieving for Artemis and several of which have expressed the desire to make Aqualad pay, just had an encounter with her "murderer"? Why wouldn't the animators show him having a reaction to that? Are we supposed to assume he's just blithely accepting that M'gann saw Aqualad, the guy who for all intents and purposes killed her best friend, and nothing terrible happened? Either Nightwing has completely lost touch with the feelings and emotions of his team (likely, he let them think Artemis was murdered, let Bart and Gar and Jaime get captured and tortured, and let the Cave which was the home of several team members get blown to smithereens), or he doesn't care that M'gann has possibly taken revenge on Kaldur. Which means it was part of the mission or overall plan, or at the very least he was prepared for it.
Obviously this is not going to be a very popular theory. I'm a little afraid to spread it around. Because heaven forbid anyone question Nightwing or try to hold him accountable for his part in this whole mess. See: fandom's over the top reaction to Wally's very justifiable anger at him after "Darkest". But something just isn't adding up in my head and all the ideas I have to connect the dots are terrible and reflect poorly on someone, whether it's the writers for handing people the idiot ball, or Nightwing for possibly not caring about Kaldur's fate.
...Everything about this episode hurt. Nothing about it will ever be okay.