Amenadiel's Necklace, also known as The Key, is the third piece of the Flaming Sword, acting as the strength that binds the sword together. After the Flaming Sword was split apart, it was given by God to his favorite son Amenadiel who was unaware of the Key's true purpose.
While active, the necklace is shown to have the same corrupting effect over time that Azrael's Blade has on humans. However, the corruption works slowly and wears off after the necklace's powers are deactivated from Azrael's Blade being removed from the Earth.
After God breaks the Flaming Sword into three pieces to insure Lucifer Morningstar didn't have it, he gives the Key that binds them to Amenadiel for safekeeping. However, Anemadiel was unaware of what he has and simply turned the Key into a necklace that he enjoys wearing.
He wears the necklace for centuries, until, on one of his many trips to Earth to send Lucifer back to Hell, a robber shot him and stole his necklace. Amenadiel is forced to make a deal with Lucifer where, in exchange for helping get the necklace back, he lets Lucifer stay on Earth.
Six years later, after Goddess figures out that the Blade of Death was one of the missing pieces of the Flaming Sword, Amenadiel and Lucifer learned from the Flaming Sword book about the Key that was given to God's Favorite Son. As the two attempt to figure out what this means, Amenadiel's necklace levitates towards the Blade, causing Amenadiel and Lucifer to realize that it is the third piece.
A hesitant Amenadiel hides his necklace on Dan Espinoza so that Lucifer can't use it to complete the Flaming Sword. Lucifer later retrieved it from Dan and ultimately used the Flaming Sword to send Goddess into a Void to create her own universe. Afterwards, Lucifer removed the necklace from the Flaming Sword and tossed the other two pieces into the Void, but hanged on to the necklace. Lucifer then returned Amenadiel's necklace to him.
Michael sought Amenadiel's necklace in order to complete the Flaming Sword, Gabriel having recovered the other pieces from Goddess' universe. It's revealed that a morgue tech stole the necklace from Caleb's body and eventually sold it to TJ Ross who is granted superhuman strength by it. Dan is captured and eventually killed by Vincent Le Mec and his mercenaries who are searching for the necklace on Michael's orders. With his last words, Dan manages to pass on a warning about Caleb, causing Amenadiel to put the pieces together about what Michael is up to.
Michael kills TJ and gains Amenadiel's necklace, thus completing the Flaming Sword. During the Battle for Supremacy, Lucifer and Chloe Decker manage to trick Michael and remove the Key from the Flaming Sword, but Michael killed Chloe in retaliation. After Lucifer resurrects Chloe, she awakens with the necklace still in her hand and she is able to use the strength that it gives her to beat Michael into submission before nearly killing him with Azrael's Blade.
After defeating Michael, Lucifer puts the pieces of the Flaming Sword into his vault for safekeeping. However, Chloe, becoming addicted to the strength that it gives her, removes the necklace from the safe. She uses the strength to knock a suspect unconscious with a single blow. Chloe attempts to give it back to Lucifer, but he allows her to keep it.
Feeling bored, Chloe spars with Mazikeen in her apartment until Maze grows tired and left. The changes that the necklace made to her body allowed Chloe to travel to Hell with Lucifer as a living person. Chloe later uses the necklace to fight a bunch of criminals with Lucifer.
The necklace's power begins to corrupt Chloe, causing her to hide Azrael's Blade after Lucifer decides to return it to Heaven which will deactivate the necklace's powers, thus depriving Chloe of her new abilities. The corruption gets to the point that Chloe nearly kills Lucifer before she returns to her senses. Chloe allows Lucifer to return the Blade to Heaven, but not before Lucifer allows her to use the necklace's powers to speak with the ghost of Dan for a few hours. Once Lucifer returns Azrael's Blade to Heaven, Chloe's powers from the necklace stop working and she becomes once again unable to see Dan's ghost even while he's in the same room as her.
The necklace, as the strength that holds the Flaming Sword together, bestows several powers upon the user. However, these powers are only active while the Blade of Death is on Earth otherwise the necklace is just a piece of metal. The necklace's powers include:
- Levitation: The key is drawn towards the Sword and will levitate towards and point to the other two pieces while in close proximity to the other two pieces.
- Super Strength: The key, being the strength that binds the Sword together, lends its strength to whoever holds it. It allowed a man to resist two attacking angels, only dying when Michael caught him by surprise from behind. While holding the key in her hand, Chloe Decker was strong enough to throw Michael around with just one hand and beat him into submission despite Michael's immense power.
- Biological Modification: As it strengthens the body to celestial levels, the key allows a living human to be capable of surviving the journey between different dimensions, allowing Chloe Decker to travel to Hell while still being a living human. It also makes a human capable of breeding with an angel who has all of their power without the angel temporarily losing their power to do so.
- Superhuman Stamina: The key gives humans stamina comparable to that of an angel, noted that it doesn't confer anything if the person already possesses supernatural strength.
- Up until Ameandiel places his necklace on Caleb Mayfield's body, it appears in almost every episode that Amenadiel does, although its true significance is not known until "Sympathy for the Goddess".
- What Chloe and Lucifer do with the necklace following "The Murder of Lucifer Morningstar" is unknown as its powers are gone and neither Chloe nor Amenadiel are seen with it afterwards.
|#2||"Lucifer, Stay. Good Devil."||Appears|
|#13||"Take Me Back to Hell"||Appears|
|#2||"Liar, Liar, Slutty Dress on Fire"||Appears|
|#8||"Trip to Stabby Town"||Appears|
|#10||"Quid Pro Ho"||Appears|
|#13||"A Good Day to Die"||Appears|
|#15||"Deceptive Little Parasite"||Appears|
|#17||"Sympathy for the Goddess"||Appears|
|#18||"The Good, the Bad and the Crispy"||Appears|
|#1||"They're Back, Aren't They?"||Appears|
|#4||"What Would Lucifer Do?"||Appears|
|#8||"Chloe Does Lucifer"||Appears|
|#11||"City of Angels?"||Appears|
|#14||"My Brother's Keeper"||Indirect mention|
|#26||"Once Upon a Time"||Appears|
|#3||"O, Ye of Little Faith, Father"||Appears|
|#4||"All About Eve"||Appears|
|#6||"Orgy Pants to Work"||Appears|
|#8||"Super Bad Boyfriend"||Appears|
|#11||"Resting Devil Face"||Indirect mention|
|#15||"Is This Really How It's Going To End?!"||Mentioned|
|#16||"A Chance at a Happy Ending"||Appears|
|#1||"Nothing Ever Changes Around Here"||Appears|
|#2||"Buckets of Baggage"||Appears|
|#3||"Yabba Dabba Do Me"||Appears|
|#4||"Pin the Tail on the Daddy"||Appears|
|#5||"The Murder of Lucifer Morningstar"||Appears|
- Lucifer: 2.17: Sympathy for the Goddess
- Lucifer: 3.11: City of Angels?
- Lucifer: 2.18: The Good, the Bad and the Crispy
- Lucifer: 3.01: They're Back, Aren't They?
- Lucifer: 4.08: Super Bad Boyfriend
- Lucifer: 5.15: Is This Really How It's Going To End?!
- Lucifer: 5.16: A Chance at a Happy Ending
- Lucifer: 6.01: Nothing Ever Changes Around Here
- Lucifer: 6.02: Buckets of Baggage
- Lucifer: 6.03: Yabba Dabba Do Me
- Lucifer: 6.04: Pin the Tail on the Daddy
- Lucifer: 6.05: The Murder of Lucifer Morningstar