Warning! Unmarked spoilers below!
Penny will turn out to be immune to Darth Nihilus's Force Drain.
It's already been established that Darth Nihilus's Force drain and his ability to influence minds have no effect on droids as demonstrated with Alpha and his team. So when Penny comes face-to-face with Darth Nihilus, he will try to use his Force drain on her, only to be shocked to discover that it doesn't work.- Partially confirmed. Although Force Drain does hurt her and drains her Aura, it fails to outright kill her since her body is a mechanical shell. This is enough for Nihilus to notice and he stops trying to use Force Drain on her for the remainder of the Final Battle.
Darth Nihilus won't be able to destroy Salem
Word of God has established that the Two Brothers are far more powerful than Nihilus could ever dream of becoming. It stands to reason that since Salem's curse of immortality was given to her by the Brother Gods, Nihilus's Force drain will fail to kill her like everything else.- Jossed. Although it's stated that Nihilus has become more powerful than Salem, he never gets the chance to confront her as he is defeated during the Fall of Beacon.
Ruby's Silver Eyes will be the key to defeating Nihilus
Silver-Eyed Warriors are capable of petrifying Grimm with their power. This version of the Grimm are beings made of pure Dark Side energy. Nihilus is a dark side aberration, so logically Ruby's silver eyes should also affect him. In addition, the silver eyes were a gift from the God of Light, who is stated by the author to be stronger than Nihilus.- Confirmed. By combining the magic of the God of Light with the Fall Maiden's power, Ruby unleashes a blast of pure Light Side energy from her eyes that exorcises the Dark Side from Jaune's body and disrupts Nihilus' control long enough for Jaune to kill himself.
The vision Nihilus showed Jaune of him being experimented on by Atlesian scientists while Ozpin talks about disposing of the Mask is the true future, just not in the way he imagines.
Jaune will somehow manage to retake control of his body long enough to separate Nihilus's spirit from his body and put it back into the mask. He will then voluntarily enter a coma so Ozpin and Ironwood can figure out a way to help him be rid of Nihilus's influence entirely while they try to destroy the mask.- Jossed. While Jaune does briefly regain control of his body, he then stabs himself with his sword, killing himself and Nihilus. The vision of a possible future Nihilus shows Jaune was just that: a possible future, nothing more and nothing less.
