Agents of some secret government agency or sinister foreign power running a test.

He holds the same sinister power over all those other beautiful girls of his black magic cult.

Aye, but there's a sinister power in his, and delighted he is to put it to use on some poor soul.

Suddenly a monstrous flux of sinister power loomed, dark and evil.

The superstitious said his sinister powers came from witchcraft.

There was sinister power about it that was far more lingering than the ugliness of Morgaine's older-lesser-weapons.

Jack uses his sinister powers to keep the boys in line.

The Law, according to him, was not of God, but of "the sinister power."

Perhaps he really is an arrogant servant of some sinister power, Akabar thought.

Some of the dragons beat their wings nervously, sensing, perhaps, the sinister powers summoned to conjure this new threat.