«I must also warn everyone that by including Del Toro (as a villain), the chances of Kylo Ren dying have increased ten-fold. If Del Toro is confirmed as a villain, Kylo’s survival is no longer critical to the plot. His survival is no longer necessary past the end of the series (or eventhrough it), on a narrative level. So there’s that. (...)
Unless he’s the main protagonist - which he is, because he moves the plot forward and everyone reacts to what he does - then he absolutely cannot die.
He still has to teach Rey. She won’t survive without him.
if Del Toro’s a villain, he’s no longer the principal antagonist either. (...) It means they can do SO much more with his character, if Del Toro becomes the principal antagonist. I am incredibly excited.»
I like to think this is a possible way...