Cap au Diable Demons
These strange beings of living energy can be found as enemies in City of Villains. They will spawn only in the zone of Cap au Diable, and only in the PTS stations. The monstruous Deathsurge is the only exception to this rule and may spawn in several points in the neighborhood of New Haven.
Cap au Diable demons official info (Copied from the City of Villains official site  ):
The imposing demon like visage of Mount Diable is shrouded in mystery - surrounded by tales of an entombed demon, mystical spirit cages, and selfless heroes sacrificing their own souls to save the people of the island.
Tapping into this mountain, Dr. Aeon’s “Power Transfer System” (or PTS) has brought unparalleled wealth and prosperity to Cap au Diable. The sheer voltage created by the PTS has confounded scientists and this pulsing source of seemingly limitless energy is a matter of much debate among those who do not trust Aeon.
The anti-technology Luddites are the most vocal opponents to the PTS. These sometimes violent activists suspect that the legends about the Mount Diable demon may contain a kernel of truth. Marshal Brass also fears that the power system is much more dangerous than Aeon is willing to admit. Such fears are encouraged by the strange energy creatures that seem to seep from the system’s snaking cables spreading across Cap au Diable.
These terrible demons are fearsome beings, composed entirely of crackling light and energy. Lingering around the power transfer stations, some believe that these entities live off the energy produced by the PTS. Others believe that they are intentionally spawned by the PTS itself.
These gremlins, turbulent with arcing electricity, appear to direct their destructive rage onto the transfer stations transformers and conductors, only attacking people that interfere with their aggression against the PTS. That they are attacking the very system that spawns them suggests that they may in fact have some nefarious purpose not yet fully understood.
These terrible little monsters somehow live inside the Cap au Diable Power Transference System. Perhaps there is more to the "PTS" than meets the eye. There are certainly rumors. Many wonder why the PTS is covered in glowing sigils. Could that have something to do with these supernatural nuisances?
Main Article: Deathsurge
This electrical horror has sprung forth from Doctor Aeon's Power Transference System! Could this be a side effect of tapping into Mount Diable?
Ball Lightning (Ranged, Damage over Time, Energy) Targeted Area of Effect, Energy, Foe -Endurance
Hurls a highly charged ball of lightning that explodes on contact. Ball Lightning deals good damage in an area and also drains some endurance from each target it hits.
Short Circuit Point Blank Area of Effect, Moderate Damage over Time, Energy, Foe -Endurance, -Recovery
Releases a burst of electrical energy around you, shocking all nearby foes. This highly accurate discharge deals Moderate damage over time, drains a lot of Endurance from the targets and renders them unable to recover Endurance for quite a while. Additionally, Short Circuit deals extra damage to most robots and mechanical foes. Short Circuit is very effective when used with your other Endurance draining powers. Damage: Moderate, Recharge: Slow .
Thunder Strike Targeted Area of Effect, Smashing/Energy
A massive attack. You smash your foes with all the power of a lightning bolt. The pummeled victim takes tremendous damage and may be Disoriented. Any nearby foes may be knocked down and take some damage from the shockwave.
The Cap au Diable Demons have learned not to mess with you.
This living spark is a capricious sort.
You have helped defeat Deathsurge.