Luther Shrike

Luther Shrike was a human that liked to collect rare supernatural items.

Background
In the 19th century, he made a deal with Barthamus to heal his terminally ill son. Barthamus held up his end of the deal, but allowed Luther's son to die a few years later of drowning. Luther was eventually dragged to Hell by Barthamus' hellhounds when the terms of his deal were up, but by then he had managed to get his hands on Barthamus' human bones. Using the bones as leverage, Luther forced Barthamus to resurrect him and grant Luther immortality on his property. Luther held onto Barthamus' bones to force Barthamus to leave him alone.

Season 13
Barthamus, however, sets up another idea to reclaim his bones. Aware of Jack being missing, he stole King Solomon's tracking spell in order to get the Winchester's aid.

Somehow, the rumor spread about Barthamus activity into Asmodeus inner circle, Asmodeus sent his messenger to meet Luther. However, Luther replied with trap and exorcised the messenger and said that he doesn't work under demons and he has been ready for the day that he will encounter Barthamus once more.

Sam under guise as a supernatural collector, was able to infiltrate Luther's property and placed Dean and Alice, which further summoned Grab. They managed to make it to his vault. However, Luther sensed their activity and compromised Sam. After a short fight, he managed to go to his vault room and killed Grab.

While Alice fled the scene, Dean later managed to combat Luther. Sam arrived at the scene and told Dean that Luther is immortal. Dean later disabled Luther by hitting him in his jaw to render him unconscious. When he regained his sensed, he later told the Winchester about vault's booby trap mechanisms. Sam and Dean later fed him to his own darts booby trap, since they knew it wouldn't hurt him as he is immortal.

After managing to disable Luther's darts booby trap, and thanks to Alice's safe cracking skills, Sam, Dean, and Alice managed to stole the cache. But Luther was able to escape the scene and later ambush them with his truck, the car chase ensued. Sam later shot the truck's tire, disabling it.

Luther revealed the nature of Barthamus, what he had done and the deal. He also revealed the content of the cache, human bones of Barthamus, that he used for blackmailing him. After revealing all that he knew, Barthamus appeared and killed him by decapitating him.

Powers and Abilities
Due to his deal with Barthamus as part of the deal to keep him at bay, Luther was granted Immortality so long he stayed on his property. Many years later, in order to counter against supernaturals like gifted humans, monsters, angels, and demons, he learned some skills for countering them.
 * Immortality - As part of his deal, Barthamus granted him immortality, as long he stayed on his property. Due to this, any means that can normally kill humans like fatal stabs and gunshots cannot harm him, so long he stays on his property.
 * Supernatural Awareness - Describing himself as "book guy", he was apparently very well learned in order to combat supernaturals. He is very well learned about supernatural creatures and its lore, including killing demons by burning their human bones. He knows about making wards and booby traps in order to secure his property. In order to combat demons, he knows about demon trapping and exorcism. He also knows how to make potent darts using a combination of silver, arsenic, holy water, and holy oil that is potentially able to disable or kill monsters, humans, demons, and angels if they were somehow able to break into his vault.
 * Magic - He is also well learned in magic. As he was able to install wards and magical contraptions in order to secure his vault.
 * Sensing - He was able to sense any movements inside his property.
 * Martial Artist - He is skilled in both hand-to-hand and armed combat. He was able to fight Sam and disable him.

Weaknesses

 * Connection to his property - As long he stayed on his property, he couldn't be harmed or killed. If he managed to get out, his immortality would wear off, making him vulnerable enough to kill.
 * Mortality - Barthamus decapitate his head with machete, killing him.

Killed By
After revealing the truth behind Barthamus to Sam and Dean, Barthamus sliced his head off.
 * Barthamus

Appearances

 * Season 13
 * The Scorpion and The Frog