Invulnerability

Castiel is invulnerable to Ruby's knife.

“	"Oh, go ahead and shoot me, if it makes you feel better. Besides, I could use a good... you know... tickle."	”
	— Patrick in The Curious Case of Dean Winchester

Invulnerability is the ability to withstand any amount of physical damage or harmful force, causing little if any harm or pain to the individual. All beings with this ability bodies', except for The Darkness, God, and Death, draw blood and can be pierced and penetrated by earthly objects but it doesn't do anything.

A high Invulnerability does not necessarily implicate many abilities. Leviathans are difficult to kill but posses few abilities.

A low Invulnerability does not necessarily implicate few abilities. Witches can be killed by anything that would kill a human, but powerful witches can cast spells that can even affect Leviathans and Seraphs.

Characters with this ability

Nigh Invulnerability

These supernatural entities are next to indestructible and can likely only be killed by comparably powerful beings or more powerful ones. Seeing as Death's scythe can kill even him, it can likely kill God and because the First Blade is powered by the Darkness, it might be able to kill Death and maybe even God.

• Cain - As the bearer of the Mark of Cain and the very first Knight of Hell he can't be killed by normal means; only the power of The First Blade or The Darkness can kill him. God and Death can also kill him but not before they remove the Mark.
• Lucifer (formerly) - Since Lucifer once bore the Mark of Cain, he was almost indestructible.
• Death - Death had a considerable immunity against nearly all kind of physical and supernatural attacks, and he was close to being indestructible. However, he was killed by his own Scythe.
• God - God is close to being completely invincible and nearly nothing can hurt him at all.  However, Death has claimed that he can reap him. The Darkness is also capable of hurting, and killing him.
• The Darkness - The older sister of God. Due to her destructive nature, she was sealed away.  More powerful than God or Death, she is beyond destruction by anything except God himself.

Advanced Invulnerability

These beings are among the most resilient and powerful in the Supernatural universe, they have very few weaknesses and could only be killed by nigh-omnipotent forces or very rare and powerful weapons.

• Archangels - The Darkness, God, and Death can kill them without much effort. When it comes to weapons, only Death's Scythe, The First Blade and an Archangel Blade can destroy them.
• Eve - Eve can only be killed by phoenix ash, The First Blade, Death's scythe, or the Darkness, God, and Death.
• Leviathans - Nigh-indestructible beasts created by God. Weakened only by Borax, beheading, and hunger. Magic can at least affect them. Killed only by each other, or by bibbing (eating themselves), by the Bone Of Righteous Mortal Washed In the Three Bloods of Fallen, The First Blade or primordial entities like the Darkness, God, or Death.

Medium Invulnerability

These Supernatural beings have certain vulnerabilities, however could also be killed be some higher-tier entities like archangels.

• Alphas - Vulnerable only to the weaknesses of their respective species, but are more resilient, and sometimes even immune to some things. In the case of the Alpha Vampire, he is specifically stated to be invulnerable to a device capable of effortlessly killing normal vampires with the Colt being the only known weapon capable of harming him.
• Angels - This includes Seraphim, Grigori, Cupids and regular angels. Vulnerable only to each other, an angel blade, The First Blade, powerful magic, Holy fire, Death's Scythe, Leviathans, Eve, Archangels, Death, God, and the Darkness.
• Princes of Hell - Killable by The Colt, The First Blade, Death's Scythe, Lance of Michael and Higher-Tier Entities.
• Knights of Hell - Killable by The Colt, The First Blade, Death's Scythe, Lance of Michael and Higher-Tier Entities.
• Deities - Weakened only by particular weapons, rituals, or by more powerful beings.
• Fairies - Fairies can be killed by strong electromagnetic waves. Iron can hurt fairies and dark fairies burn when touched with silver.
• Famine, War, and Pestilence - Weakened only by the removal of their ring, however when they assume human forms, they can receive damage. Only Death's Scythe can kill their physical form but won't destroy the attribute. The First Blade's effect on them is unknown.
• Ghosts - Ghosts can be sent to heaven or hell by the destruction of the object or remains that allows them to remain on Earth, or by resolving the issues keeping them there.
• Jesse Turner - Despite his nigh-omnipotence, he is still vulnerable to many common demon weaknesses.
• Nephilim - Shrugged off a punch from an angel. Can be killed by an angel blade.
• Samhain - The unique multicolored Demon Samhain was able to generate White Light, this indicates that he is probably similar vulnerable like White-eyed demons. He was also immune to Iron.
• The Wicked Witch - Could be killed by the Ruby Slippers.
• White eyed Demons - Highly resistant to salt, holy water, iron and palo santo, can't be killed by regular angel's smiting touch. Killable by The Colt, The First Blade, Death's Scythe, and Higher-Tier Entities.
• Whore of Babylon - Can be killed by a stake made from a Cypress tree in Babylon wielded by a servant of Heaven.

Low Invulnerability

These Supernatural beings have certain non-physical vulnerabilities, however could also be killed by a lot of higher-tier entities like angels or powerful demons.

• Black-eyed and Red-eyed demons - Angel Blades, The First Blade, The Colt, Demon Bombs, spells, and Ruby's knife can kill them.
• Dragons - Vulnerable to blades forged with Dragon's blood.
• Hellhounds - Can be killed by an angel blade.
• Jefferson Starships - Can be killed by beheading with a silver blade.
• Phoenix - Weakened by iron, can be killed by the Colt.
• Siren - Can be killed by a bronze dagger coated in the blood of someone under its influence.
• Vampires - Beheading, smiting, Leviathans, and Additive 3.0 can kill them.

Minimal Invulnerability

These supernatural beings have a many vulnerabilities, can often be killed by conventional means - like fire, beheading and silver knives, and higher-tier entities.

• Amazons - Can be killed by everything, that kills a human as well.
• Arachne - Vulnerable to beheading.
• Changeling - Can be killed by fire, will immediately die if his mother is killed.
• Djinn - Killable by brain damage and a silver knife dipped in dog's blood.
• Ghouls - Can be killed by decaption or considerable brain damage.
• Kitsune - Can be killed by destroying their heart or starvation.
• Okami - Can be killed by Wood chippers.
• Pishtaco - Can be killed by silver.
• Rawhead - Can be killed by electricity.
• Shtriga - Vulnerable to iron bullets, when they are feeding.
• Skinwalker - Can be killed by silver.
• Wendigo - Can be killed by fire or silver.
• Werewolf - Can be killed by silver.
• Witches - While the spells of powerful witches can affect even Leviathans or Seraphs, they are ironically still vulnerable to everything that could kill a regular human.
• Wraith - Can be killed by silver.