In hindsight with all of the speculation about Lillie and Nihilego. As nothing is official or set in stone. Its the one entity that Lillie is scared of. Even though Silvally cured some of the fear. It still probably exists. I never thought that pairing was plausible because I always thought that if for whatever reason it was to be caught. It would be by Gladion instead. The older brother helping and assisting his younger sister master her fears. It's a great story in my opinion.