True evil is hard to spot. It's never as obvious as a pair of demon wings, a red eye, or a dark cloak.
True evil is cunning-- it lies and deceives to get what it wants. True evil throws up a veil of falsehoods to protect its true identity. On the outside, it may appear kind, virtuous, sympathetic, familiar, even beautiful.
But once the skin is pierced, the blood flows, and it flows red.