All the speculation about KOTOR being part of the canon now can be said to be true, as the final two episodes culminate in Malachor, especially in the Sith Temple. Kanan said: "Malachor has always been a forbidden for the Jedi."
That, always part is a lie, because those the don't know the history of Old Republic, doesn't know that there used to be three factions that were all force users. These were Jedi, Sith, and Grey, in which Grey used to a neural faction. They even were able to take powers from available to Sith and Jedi, while they developed their own Force ideas.
I haven't personally studied canon so much that I could say there used to be this sort of thing, but when you see Ezra picking up certain lightsaber, you immediately recognize the shape and connect it to Kylo Ren's own design.
In those years Luke became a Jedi Master, especially going into hiding, Kylo Ren possibly visited Malachor V's jedi temple. He might have prowled to same grounds to find force artefacts, and pieces of Mandalorian armour. If you look at his helmet, you see it being advanced from Mandalorin standards that you can see for example in Sabina's (and Boba Fett's) helmet.
What I'm trying to say is that there are so much history in Malachor V, and especially in the Sith Temple that a viewer can be drawing certain conclusion on the whole history of movies. But what they might know about the Inquisitors is that they were a true Sith project to create guardian units.
Darth Vader used them as shock troops under Emperor's command. And Darth Sidious has legends written on those walls. So it's a no surprise to find that the Emperor dumped Maul into the temple. Only this time Maul is the Master and Ezra his apprentice.
But I don't for one second believe that Maul isn't plotting against the Emperor and his Inquisitors, where I believe Vader being the Inquisitor. However, what also is interesting is that Maul has adopted Ashokas's ideas about being against the ultimate faction, and thus he's rebelling against Sith in the home territory.
So, one could easily believe that Maul present darker shades of Grey Order and Ashoka lighter side. And that makes Ezra's training especially interesting because he has shown tendencies to both sides of Force. He could actually become under Mauls' and Ashoka's guidance first true Grey in a very long time. Only now that task lies on Kanan's shoulders.
But does that mean we are going to see Ezra and Kanan in the movies? My answer is maybe.
