9. Sons Of The Serpent
The Sons of the Serpent are a particularly unpleasant group of supervillains, initially formed in order to do violent hate crime to 'divide America', which somehow sounds worse than the humble villain goal of ending the world.
The group would go through several different formations, all of which would see them led by some rich maniac willing to spend their entire insane amount of wealth on weird occult stuff or systemic oppression, which are also coincidentally some of the worst things you could ever spend your millions on, only narrowly beaten out by fidget spinners.
One of the most unnerving parts about the team is their plots vary from forcing Daredevil to out his true identity to the public, to kidnapping people to use as test subjects for evil experiments, with their constantly changing end goals making them also impossible to predict - not helped by the lack of real solid knowledge we have about the organisation.
Though they aren't as powerful as, say, the Masters of Evil, the mystery that surrounds the Serpents makes them deadly, as you have no idea when they'll appear, or what they'll do.