WARNING: The following contains major spoilers for The Sandman Universe/Locke & Key: Hell & Gone #1 by Joe Hill, Gabriel Rodriguez, Jay Fotos and Shawn Lee, on sale now.

The Sandman Universe/Locke & Key crossover event has finally arrived, and it has introduced the mysteries of Key House to the world of the Endless in some truly incredible ways, and it's brought ut some keys into the fantastic new world to0. And in pursuit of her larger goals, Mary Locke has just left one of her family's most powerful weapons known in the hands of the last person who should have it, Roderick Burgess.

In the 12long years since the events of Locke & Key: In Pale Battalions Go!, Mary Locke has watched her father's health and mental state deteriorate over the agonizing loss of yet another child as well as his doting wife. Eager to do anything she can to save her brother's soul and put Chamberlain's mind and heart at ease, Mary has stolen away to England with several of the magic keys in her possession. Arriving at the Sussex estate of legendary occultist Roderick Burgess, Mary is slow to acquiesce to his demands but eventually relents. In order to have an audience with the imprisoned Morpheus that Burgess has been keeping captive, she needs to trade him one of the keys he has heard so much about. Unfortunately, Mary gives him one of the most destructive of them all, the Matchstick Key.

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While the comics have unveiled plenty of keys throughout the course of the series, the Netflix adaptation introduced one new key in particular with some truly explosive powers. The Matchstick Key is capable of setting anything it is inserted into ablaze. When first seen on the Netflix series, the Matchstick Key is in the hands of Mark Cho, one of the original Keepers of the Keys. When Mark found out about Rendell Locke's death, he gathered every piece of information he had related to his experience with Key House before inserting the Matchstick Key into his own chest and letting it burn him and his home to the ground.

This application was seen once more during In Pale Battalions Go! when Jonathan Locke brought the key with him to the frontlines of the First World War. The Matchstick Key might not be as outwardly powerful as an artifact such as the Crown of Shadows, and it certainly doesn't have the world shaping capabilities that the Anywhere Key opens up to its user, but it is still one of the most destructive of any of the magic keys that have been introduced so far. That it is now in the possession of someone as vile as Dream's foe Roderick Burgess only makes things even worse.

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Fortunately, it doesn't seem as though Burgess regards the Matchstick Key as much more than another mystical trinket to add to his collection, even leaving it in the hands of his partner Ethel to light up a cigarette with. It's hard to imagine that Roderick doesn't understand the sheer power of the item currently in his possession, nor is it likely that he won't soon enough try to use it as a means to disastrous ends. She might not know it yet, but Mary Locke just added fuel to a fire that desperately needed putting out

Luckily, the Matchstick Key hasn't been seen in any of the modern Locke & Key comics, leaving a good chance that Roderick is the final owner of the key before it slips into obscurity. Then again, with Sandman slated for his own Netflix adaptation soon enough, it could open the door for yet another crossover between these two fan-favorite franchises.

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