Whether you've been keeping up or not, the Marvel Cinematic Universe has a lot of weapons in it. From the Tesseract to the 0-8-4, the universe is jam-packed with things that can do anything, from hurt you to obliterate the planet you live on. And it's these artifacts which have become extremely popular among fans. The thing is, thesy always seem to move from holder to holder, and sometimes they get lost along the way.

When these items do get lost, fans occasionally forget about them. With the exception of the Infinity Stones, fans usually seem certain of these weapons never resurfacing. However, the MCU has shown us time and again that nothing stays gone forever; Chitauri tech being a perfect example. Netflix's Luke Cage series brought back Chitauri tech in the form of Judas, a type of metal created from Chitauri tech leftover from the Battle of New York. Hammer Industries turned the alien tech into bullets that can harm even Luke Cage. At the same time, Agents of SHIELD has also introduced tons of other weapons / artifacts with similar origins. In lieu of that, we've compiled a list of 15 secret weapons still lurking in the MCU, some of which may resurface in coming years.

15 HAMMER TECH EXO-SUITS

Hammer Industries' exo-suits made their first appearance in Season 1 of Netflix's Luke Cage series. The tech was developed after the bods at Hammer got their hands on Chitauri tech left over from the Battle Of New York. They managed to convert some of the alien tech into a prototype metal known as Judas. The metal was then used to craft bullets, gauntlets, and eventually the exo-suit worn by Diamondback.

So far, we've only seen one ex0-suit in action but that doesn't mean Hammer Industries doesn't have more. The suits have proven to be quite formidable when paired with an equally adept human being, so the company likely has more in development — if they're not being used already. Who knows, maybe they'll even make a comeback in Season 2 of Luke Cage, which premieres on June 22nd.

14 THE SUBSTANCE

The Substance was first introduced in Season 1 of The Defenders, revealed as being The Hand's source of immortality. Basically, it's a serum derived from crushed up dragon bone, and one happens to be buried under Midland Circle in New York. Danny Rand finds the bones after unlocking the door built to keep them from The Hand. Bear in mind that The Substance appears to be out of everyone's reach... for now.

With the last dragon bones buried under a pile of rubble, there's no way to make more Substance. However, Matt Murdock was pulled from the rubble and resuscitated at the end of The Defenders, so there's a good chance some of those dragon bones were recovered, too. If they were, more of the Substance can be created and could pop up in Season 3 of Daredevil. It's yet to receive a release date but filming schedules impress upon us that a release may come as early as July, 2018.

13 CLAIRE'S CLAWS

In Netflix's corner of the MCU, Claire Temple has become one of its most foundational staples. She's been featured in several of Netflix's Marvel series, brought the Defenders together, and could even become a hero herself. As the heart of the Netflix team of heroes, Claire is a hero already, but she may become one who engages in the action like her pal, Luke Cage, especially now that she has the right tools for the job.

What we're talking about are the cat-like claws she received from Colleen Wing in Season 1 of Iron Fist. There was no discussion of the item at the time but rumor has it that Claire will become an adaptation of White Tiger; the claws being evidence of this. If she is, Claire could be next in line to join the Defenders. Or perhaps, she'll partner with Colleen and Misty in a variation of Daughters Of The Dragon.

12 NEW CAPTAIN AMERICA SHIELD

In case the shout-out went over your head or under your radar, a subtle mention of Captain America's new shield was dropped in Spider-Man: Homecoming when Happy Hogan reads off the manifest of Stark's Cargo Plane. He mentions Cap's New Shield shortly before the plane is hijacked by the Vulture. It winds up crashing on Coney Island but something as durable as a shield for Cap likely remained intact.

Regardless, the shield is going to make its way into someone's hands and that might not be Steve Rogers like most of us expect it to be. Since he's presumably receiving one from T'Challa in Avengers: Infinity War ( in the form of those retractable defensive gauntlets), the one created by Tony Stark won't have a purpose — unless it was made for the next Captain America. Perhaps Bucky Barnes or Sam Wilson will pick it up in Avengers: Infinity War, which opens in theaters on April 27, 2018.

11 VIBRANIUM ENGINE FROM SOKOVIA

At the end of Avengers: Age of Ultron, Sokovia was in pieces. After Thor and Iron Man destroyed the engine keeping the city afloat, its remnants fell into a body of water. Inside of those remains was a Vibranium Engine, one that presumably got picked up by the Department of Damage Control.

Assuming the Vibranium Engine was recovered by Stark's employees from Damage Control, he has a store of Vibranium to use however he chooses. One might assume Stark would melt down the metal into raw material for a new Iron Man armor, but the more logical explanation is that Tony used the Vibranium for Cap's new shield. Of course, we should keep our minds open to Stark using it for something more ingenious than a suit of armor... or a glorified frisbee.

10 ADAM WARLOCK'S COCOON

Before you get your hopes up, Adam Warlock won't be appearing in the MCU until Guardians Of The Galaxy Vol. 3, at least according to James Gunn. Now, that may or may not be what takes place but the seeds of his arrival have been sown nonetheless.

After GOTG2 introduced Warlock's cocoon in one of the post-credits scenes, it's pretty clear that Warlock is going to emerge at a crucial point in the MCU timeline. When he does, Warlock is undoubtedly going to impact the universe significantly enough to see the Avengers' become involved. They'll be in contact with the Guardians of the Galaxy after Avengers: Infinity War, so partnering up on a side mission is feasible. Plus, a crazed Adam Warlock -- or his evil doppelganger in the Magus -- seems like a threat worthy of the Avengers' attention. Guardians of the Galaxy Vol. 3 is set for a 2019 release date.

9 B.A.R.F.

The Binarily Augmented Retro-Framing, or B.A.R.F., is a device used to relive memories for therapeutic purposes. Stark first unveiled the tech to an MIT graduating class in Captain America: Civil War. In that scene, Stark glossed over the fact that it cost him millions to create, but he developed the tech regardless. Stark only used it once but it looks like he'll be using it again, this time in Avengers 4.

Recent photos off The Avengers 4 set have shown most of the original team back at the Battle of New York. An explanation hasn't been made public, but rumor has it that the emblems and wristbands they're wearing is the newest version of Stark's B.A.R.F. tech. Though, the whereabouts of Black Widow and Hawkeye are of much more interest here, seeing as how they're not present. Avengers 4 is scheduled to release on May 8, 2019.

8 EXTREMIS

It's been some time since the last we heard of Extremis, but that doesn't mean the revolutionary tech is gone for good, as is evidenced in Agents of S.H.I.E.L.D. The finale of Iron Man 3 also ended on a vague enough note where one could assume that Stark did what Killian and Mia Hansen couldn't, and that's complete Extremis. Stark managed to "sort Pepper out," which means he probably cracked the code. If he did, the tech is probably lying dormant in one of Stark's vaults.

However, there is a chance Stark didn't remove the Extremis virus from Pepper's body. He might have just corrected the faulty components, making it an efficient piece of technology. Plus, Agents Of S.H.I.E.L.D. revealed that the Centipede Device stabilized Extremis. Therefore, it's feasible for Stark to have done the same for Pepper, assuming she wanted to keep the virus.

7 STAFF OF THE LIVING TRIBUNAL

At the moment, the Staff of the Living Tribunal is in the wind. With Karl Mordo taking off at the end of Doctor Strange, we'll have to wait for him to resurface for the staff to be utilized again. Most fans assume that'll be in the Doctor Strange sequel, but he and the staff could have a role to play in Avengers: Infinity War.

When Thanos completes the Infinity Gauntlet, he'll have some of the most massive power in the universe. The good news is that the Staff of the Living Tribunal could be a perfect counter to the gauntlet. It possesses the ability to control powerful magic and that's essentially what the Infinity Gauntlet is powered by... or however you choose to define otherworldly cosmic energies. The question is, can the Staff of the Living Tribunal contain the immense power of the gauntlet -- it is named after an individual in the comics whose powers dwarf that of even the Gauntlet -- or will it crumble under the weight of it all?

6 EBONY BLADE

The Black Knight wielding the Ebony Blade in Marvel comics

The Ebony Blade is one weapon that exists but has yet to be seen. It showed up during a behind-the-scenes look of the Doctor Strange set, but never made it into the final cut of the film. Since the Ebony Blade was intended for at least a fly-by in Doctor Strange, it stands to reason that a plan for the blade has already been crafted.

As for the blade's origins, it was crafted by Merlin and given to The Round Table's Sir Percy., though it became cursed after Percy used it to spill blood. Sir Percy would then go on to use the moniker of Black Knight with the Ebony Blade in hand. Eventually, the blade wound up with Percy's descendant, Dane Whitman; the character who could take over the Ebony Blade at some point down the line in the MCU.

5 GH. 325

The serum known as GH. 325 was first introduced in Season 1 of Marvel's Agents of S.H.I.E.L.D. On that series, S.H.I.E.L.D. discovered the secret facility known as the Guest House. There, Kree DNA was used to develop serums like the GH. 325 used to revive both Coulson and Daisy after their brushes with death. The bad news is that the GH. 325 appears to be out of reach.

After the Guest House self-destructed with GH and all of the research pertaining to it was buried under the facility, it was lost. No mentions of the serum have cropped up since, but that doesn't mean someone can't dig through the rubble to recover GH. 325. Matt Murdock was dug out of a similar wreckage in The Defenders, so it's fair to say GH can be recovered, too.

4 GRAVITONIUM

As it turns out, the element known as Gravitonium recently popped up back on Agents Of S.H.I.E.L.D. Fitz and Simmons discovered that the Zephyr One of the future was being powered by it. There hasn't been an explanation as to how the Gravitonium was integrated into the plane's systems but it's bound to come up eventually. At the same time, Franklin Hall's involvement will more than likely be touched upon.

We haven't heard anything about Franklin Hall since he was consumed by the Gravitonium deposit on Agents Of S.H.I.E.L.D. but his comic origins tell us that he's going to resurface as Graviton, at some point. When he does, the Agents are going to have a new threat to face — unless Graviton / Franklin Hall resurfaces in a different corner of the MCU.

3 PERUVIAN 0-8-4

The Peruvian 0-8-4 is a Tesseract powered device created in Peru,. It first cropped up in WWII but remained stuck in the wall of an Incan temple until 2013. It was then that S.H.I.E.L.D. took possession of the artifact and stored it in The Fridge. The 0-8-4 shifted hands again when John Barrett attacked The Fridge and liberated it from them. The funny thing is, Garrett wound up being disintegrated with that very device.

After a long absence, the 0-8-4 landed in the Watchdogs' hands. They almost killed Yo-Yo with it but she used her Inhuman powers to redirect it at Colonel Ramon, ending his life. S.H.I.E.L.D. recovered the device shortly after, putting it out of commission. However, we can't rule out the possibility of someone else getting their hands on the device, especially now that S.H.I.E.L.D. stores have been seized by the U.S. government.

2 BERSERKER STAFF

Another MCU weapon that seems to be buried for good is the Berserker Staff. The Asgardian artifact was left under the collapsed ruins of John Garrett's Hydra base in Cuba after Melinda May was ordered to bring the building down. Since then, nothing has been said of it and it doesn't look like Thor has gone to retrieve the weapon. However, it may be of some use to Thor in Avengers: Infinity War.

As most of us know, Thor will wield an axe instead of his signature hammer. How he creates it is anyone's guess but it's possible he'll use the Berserker Staff in some way, if it isn't his axe, Jarnbjorn, from the comics, that is. The staff is infused with Asgardian magic and metal, which could be converted into a handle for Thor's axe. He'd still need a compatible head, but there's definitely potential. After all, he's also shown wielding a makeshift new hammer with parts of Groot. Also keep in mind that other theories suggest shots of Thor struggling in the Infinity War trailer are of him inside a weapon's forge, explaining where the axe comes from.

1 THE DARKHOLD

For anyone not familiar with the Darkhold, it's a book of magic spells that give the possessor immense powers. The book currently resides in Hell — or rather the MCU's version of Hell, which is just another dimension -- but there's nothing tying it there. A potential spoiler dropped by Gabriel Luna is evidence of this...

In a 2016 interview, Gabriel Luna, the actor who plays Reyes on AoS, accidentally name-dropped Mephisto as an upcoming character. What that means is we'll see further development of Hell and that region of the MCU. At the same time, the door is open for the Darkhold to come back, too. And honestly, who doesn't want to see Vampires brought into the fold by using the Darkhold? It's happened in the comics, so why not live action? Perhaps the Darkhold will be key to giving life to the ever so popular Blade?