Here's an interesting plot twist to imagine: Neo has a mental complex about being the sidekick of the most efficient killer in Vale. Up to now, that's been Roman, but Ruby could be argued to have beaten Roman and she subsequently petrified a giant Dragon-Grimm and sent Cinder running with her tail between her legs. So, much to Ruby's horror, she's suddenly got a mute psychopath who has an obsessive desire to be her sidekick.