(warning – spoilers for Star Wars: The Force Awakens)
A quick thought about Kylo Ren and the Knights of Ren, who we do see during Rey’s sabre-vision.
All we know of why Luke went AWOL was that one of his apprentices (Ren) “destroyed everything” that Luke had tried to build. It’s never stated explicitly that Ren went all Anakin on the younglings. In fact it seems given Ren’s angst about killing Han and the Light, that he’s never crossed the line so dramatically. This is underscored by Snoke who explicitly tells him, “you are the Master of the Knights of Ren, but even you have never faced such a challenge.” (paraphrasing)
What if instead of killing Luke’s jedi in training, Ren corrupted them? Using some of that charisma and leadership skill he inherited from mom and dad, it’s plausible that he took over the Knights of Ren and lured them to the dark side. Such a betrayal of Luke’s goals would be arguably worse than just killing them. In a real sense, that truly is “destroying everything Luke worked for”…
… from a certain point of view.