It was later confirmed in an intended draft for the story that Malefor was in fact corrupted by something bigger and far more powerful than him. Yes, there would've been something/someone out there that is worse/more evil than Malefor. Also terrifying is the possibility that this entity resides in or is perhaps imprisoned in the Dark Realms beyond the Convexity dimension which acts as an airlock between them and the Dragon Realms.
Dragons capable of Poison, Fear and Shadow breaths exist but are not natural and are the result of a "dark magic".
What the apes could have possibly done to Cynder to make her into an Axe-Crazy monster. What's worse is that she killed numerous of dragons during and after the war before she was 12.
The Golem from Dawn of the Dragon is pretty horrific, especially when Spyro and Cynder are escaping the catacombs and encounter it during several quick time sequences. If you fail to press the correct button, you're treated to a scene of Spyro and Cynder either getting crushed to a pulp or devoured whole, complete with chomping sound effects.