Enhanced Durability is the power to withstand physical and/or magical harm that would otherwise be lethal. This is not a term or label of a power used in-universe, but rather describes a trait that is suggested to be inherent to some demons, witches and Whitelighters.
Enhanced durability allows users to survive attacks that are otherwise lethal. It also grants users protection against the effects of their own powers.
This ability is not synonymous with invincibility, and beings with this trait can still be vanquished or killed by powerful magical attacks or spells. It is a common attribute among powerful magical beings, most of which are upper-level.
The beings with this ability have all, to some extent, shown a higher resistance to pain than would averagely be possible. Some beings have been shown to experience less pain under circumstances that would be highly painful, while other beings have been shown to experience no pain at all.
In Jingle Hell, Harry Greenwood was only minimally harmed and remained conscious after he was pushed from a height of three floors by Hunter Caine. Jada was seemingly less harmed than she should've been after being shot with an arrow in Touched by a Demon.
In Touched by a Demon, a new demonic trait showed itself in Macy when her hand accidentally lands on the stove, but she doesn’t feel anything until it’s almost completely burned through her flesh. According to Harry, the common characteristics of most demons include thickened skin with fraying nerves, which contributes to the dulling of their pain receptors.
This was demonstrated in Keep Calm and Harry On when the demon Alastor not only showed no pain after he was stabbed by a knife in his forehead, but also used it to cut his own face to reveal his demonic form without showing any sign of pain.
However, it seems that some demons can still feel pain, as Hunter Caine was visibly in pain after he was injected with the virus that he attempted to use on Niko Hamada in Other Women, and when he was attacked by the Sarcana's crows in Jingle Hell. However, this could be because both attacks were magical in nature, as when he was attacked by Mel Vera's double blades in Ambush, he showed no sign of pain and appeared to simply smoke through strikes.
- In the original series, this power was known as High Resistance, and allowed upper-level witches and demons to withstand magical attacks that would otherwise destroy them.