Not every villain has to sound like one. Perhaps, instead of having a malevolent rasp, a gloating shrill, or a booming bass, the villain's voice is instead light and low. They don't yell or intimidate, and might not even be impolite — instead, they speak with a soft tone that seems unassuming, meek, or even kind, with a soft chuckle and a sort of warm energy... hiding the menace within. The end result is something dissonant and creepy, a monster who might describe just how horribly they're going to mangle you while speaking in a voice that's anything but monstrous.
Of course, this can possibly also go in quite the opposite direction, with the villain's gentle voice highlighting their willingness to commit atrocities out of schadenfreude, their enjoyment of combat, their total lack of shame towards their actions, their casual disregard for human decency, or even their refusal to back down when confronted.
Keep in mind this doesn't always mean the character in question is a Sadist—it's just an Alliterative Name.
See also Affably Evil, Faux Affably Evil, Dissonant Serenity, Creepy Monotone, and Creepy High-Pitched Voice, and compare Wicked Cultured and Polite Villains, Rude Heroes. Note that if and when they eventually drop this soft-spoken demeanor, then that's a surefire sign things are going to get worse. Blends very well with Creepy Monotone and Evil Sounds Deep, as is uses up the low end of the voice register more so than the high end. Contrast with Evil Is Hammy, though a Cold Ham can cover both. Fairly likely to look disturbingly normal.
