For every great hero, there need to be great villains, and the bad guys in Transformers really fit that description in that franchise. The idea of a race of robots that change into vehicles seems far-fetched. However, the popular Transformers franchise has proven that even the most far-fetched idea can bring in generations of loyal fans. For decades, Transformers has captivated fans of all ages through action figures, animated shows, comics, and feature films. The heroic Autobots are some of the most iconic protagonists in all science fiction. The exploits of Optimus Prime and his loyal companions will forever be beloved.

Like with any work of fiction, however, a hero is only as good as their villains, which is where the terrifying Decepticons, Terrorcons, and others come in. The Decepticons are ruthless and will stop at nothing to gain power and see the Autobots turned to scrap metal. The Terrorcons showed up in the live-action world for the first time in Transformers: Rise of the Beasts, and showed that even the Decepticons had a challenge for the most devastating bad guys in Transformers. In the end, there are plenty of powerful advisories for the most powerful Transformers and Optimus's army, with some more menacing than others.

15 Shockwave

Shockwave was one of the most devastating bad guys in Transformers, and he showed how powerful he was in Transformers: Dark of the Moon. This was the Decepticon that roared through Chicago and brought down high-rise buildings in Chicago, mowing through them like they were nothing. However, there is one other treason that Shockwave remains one of the most powerful Decepticons. He actually managed to take out Optimus Prime. It took a modified Optimus to finally take down Shockwave, and he held his own throughout the entire fight.

Shockwave is a giant Transformer villain, and he cares little about who he hurts, kills, or destroys when he rampages. He has a powerful ray-gun mode and the cannon emits beams of energy portent enough to destroy just about anything. He is even strong enough to hurt Transformers like Optimus Prime and Megatron. He can also fly in robot mode, one of the very few bad guys in Transformers who can achieve that.

14 Scourge

Scourge was one of the main bad guys in Transformers: Rise of the Beasts, as he traveled to Earth to seek out the Maximals, who had been in hiding for centuries. Scourge proved how powerful he was in the prelude, as Unicron led him and his Terrorcons to the Maximals' planet to destroy them. Only Optimus Primal and a select few escaped to prehistoric Earth, and Scourge proved he was the right choice to be Unicron's right-hand warrior. When Scourge reached Earth, he then did the impossible.

Scourge killed Bumblebee. This was a massive moment because Bumblebee had survived every Transformers movie and was the second most important Transformer behind only Optimus Prime. That Scourge killed him proved his power levels, and it took Optimus Prime, with his back against the wall, to finally take out Scourge. The only thing that holds Scourge back is his arrogance, which usually leads to his downfall.

13 Megatron

The Decepticons are merciless and brutal, and it takes someone who excels in intimidation to, not only pose a threat to their enemies but also be able to put their followers in line. Megatron has proven time and time again that he is more than fit to lead the villainous race. With an infamous hatred of Optimus Prime, Megatron will stop at nothing to see Optimus's downfall and the Autobots bowing before him. Most versions of the Decepticons' leader also show his loath for humanity, going out of his way just to torment them for his own enjoyment.

For his part, Megatron was also the main villain for most of the Michael Bay series of Transformers movies. Megatron helped destroy Cybertron when he couldn't rule over it and sent all the Autobots on the run for their own safety. No matter how many times the Autobots stopped Megatron and seemed to defeat him, they could only slow him down, and he always returned, often stronger than he was before.

12 Galvatron

The mighty must always fall. This is even true for Megatron who, after suffering a brutal defeat in battle, is reborn as Galvatron. Galvatron retains all the memories of the fallen Megatron, except he is much deadlier. After serving Unicron, Galvatron eventually goes mad and returns to his former role as leader of the Decepticons. This new incarnation is much more menacing and relentless, not hesitating to slay even his Decepticons followers if they stand in the way of him gaining ultimate power.

In Transformers: Age of Extinction, Galvatron took on an even deadlier role. In this case, it wasn't Megatron being reborn as Galvatron - it was the humans on Earth building their own giant robot to replace the Autobots as the Earth's protector. Of course, these things never go well and in this case, Galvatron wasn't Earth's protector, but the next major villain that the Autobots had to save humanity from. To tie it back in with the past versions, the humans did model Galvatron after Optimus Prime, but with Megatron's mind/consciousness - their ultimate mistake.

11 Cyclonus

For Cyclonus, the most important thing is the Decepticon cause and the satisfaction of Galvatron. He is immensely loyal to his master and will do his bidding regardless of the downfall. He will even destroy his fellow Decepticons if Galvatron wills it. What makes Cyclonus so dangerous is his remorseless way of destroying anything in Galvatron's way. Cyclonus is one of the most powerful Decepticons, and could easily take out his master if he so desired. His steadfast loyalty prevents this though, making him a menacing adversary for the Autobots.

10 Nemesis Prime

Optimus Prime is one of the most powerful Transformers who has ever lived. His moral compass, however, keeps his power in check and is used for the good of the universe. However, remove his moral center and you get the treacherous Nemesis Prime. Nemesis Prime is an evil clone of the Autobot leader and has the same abilities without that pesky conscience getting in the way. Nemesis typically has no affiliation (although has fought alongside the Decepticons in the past). Destruction is mayhem is all Nemesis Prime cares for and takes pride in taking out any Transformer Autobot or Decepticon.

9 Devastator

The Construticons are dangerous allies of the Decepticons on their own. They each use a piece of construction equipment as their alternate mode and are fiercely loyal to the Decepticons cause. When they combine, however, you get the aptly named Devastator. Devastator is a towering being that can destroy anything in its way with ease. The Autobots are smart to fear the violent machine, and it takes everything they have to bring it down. Devastator has shown up in multiple versions of the Transformers franchise and never fails to be one of the most powerful additions to the lineup of robots.

Devastator was a little different when he showed up in Transformers: Revenge of the Fallen. In this case, Devastator was a massive combiner composed of eight Transformers (Mixmaster, Scavenger, Scrapper, Hightower, Scrapmetal, Overload, Long Haul, and Skipjack). He even took out the powerful Mudflap by consuming him, although Mudflap lived and burst out of Devastator. What is most impressive is that the Transformers couldn't beat him, and it took an experimental U.S. military weapon to take him down.

8 Lockdown

There isn't anything really special about Lockdown. He is a typical Decepticon and his main powers and abilities tie into his fighting skills. He can conceal his face in robot mode, so he can target victims, and he has several long and short-barrel guns that can do major damage to anyone. However, what makes Lockdown so impressive is that he is one of the best fighters and is ruthless, willing to do anything to outlast and take down his opponents. How strong is Lockdown? He is one of the few bad guys in Transformers who beat Optimus Prime in a one-on-one fight.

Lockdown is a bounty hunter, and he has a plethora of experience in hunting down his prey and beating them. This really helped him when planning his attacks on Optimus Prime in Transformers: Age of Extinction. Yes, he sabotaged Optimus, but all is fair in a war and Lockdown beat Prime two different times, which is something no one other than Sentinel Prime could boast from the movies. It wasn't until Bumblebee distracted Lockdown and Optimus hit his own surprise attack that Lockdown finally fell.

7 Sentinel Prime

The biggest surprise in Transformers: Dark of the Moon was when Sentinel Prime turned out to be the surprise villain of the movie. When it comes to the bad guys in Transformers, there weren't many in the movies more powerful than Sentinel Prime. He was the Autobots' leader before Optimus Prime, and he ended up rescued from the moon, where he was resurrected and the Autobots believed they had a new ally. That didn't happen. Prime made a deal with Megatron because he believed the Autobots could never win the war.

Sentinel Prime proved his power when he killed Ironhide, one of the most powerful of the Autobots' soldiers - and he did it in a way where Ironhide could never be resurrected. He then showed his true might when he defeated Optimus Prime on two different occasions, and he did it with his fighting ability alone. He almost killed Optimus and the only thing that beat Sentinel was when Megatron betrayed him. No one came as close as Sentinel Prime to destroying the Earth.

6 Trypticon

The Autobots and Decepticons usually have their missions straight. They hate each other and each one will go through all sorts of punishment to stop the other. The Decepticons are a hateful race, but when one hates not just Autobots, but their Decepticon allies, you get Trypticon. A Godzilla-esque robot, Trypticon hates every living thing and will happily destroy anything whether it is in his way or not. Trypticon's alternate form is typically an entire city, so the size of this monstrosity is massive, as is the destruction that comes along with him.

5 Predaking

When a group of Transformers combines into one being, they typically suffer to some extent. The combination of minds will oftentimes sacrifice intelligence or the ability to self-think. For Predaking, nothing could be further from the truth. The combination of the dastardly Predacons, Predaking is practically animalistic in his savage need to destroy. Predaking is able to function flawlessly, as the Predacon's minds are merged into one being. Predaking strikes fear into the cores of the Autobots and will send his advisories scrambling for cover the second he enters the battle.

4 Overlord

The Decepticons have used many superweapons over the years, but when that superweapon happens to be a Decepticon himself, all bets are off. Overlord will slay enemies, and unlike other Decepticons, couldn't care less about power. He takes pride in wiping out his opposition and is programmed to do so. Megatron has enhanced Overlord with the means to become virtually indestructible, and the Autobots know this. The Autobots are wise to fear some of their enemies, but Overlord is the stuff of their nightmares.

3 Megatronus Prime (The Fallen)

First of the Decepticons and one of the original Primes, Megatronus Prime is legendary in his power. His lust for power led him to turn against his fellow Primes, and in the process create the most deadly group of Transformers. Megatronus' shadow looms heavy in the centuries since his initial defeat, being the namesake of Megatron. Being known as The Fallen in the Transformers' Legends, Megatronus eventually returns and pulls the strings in an attempt to cause the defeat of the Autobots, and humanity.

2 Quintessa

There was nothing like Quintessa when this bad guy from Transformers movies arrived in Age of Extinction. She is on a much higher level than almost any other villain in the movies, and it isn't even close. She calls herself the Prime of Life and reveals she created the Cybetronians, and this means her powers are above almost any other villain or hero in this universe. She easily restrained Optimus Prime and then brainwashed him, showing that she could take down the most powerful of the entire Autobots and Decepticons forces without even trying.

Quintessa is also known as the Great Deceiver, and that is where she really proves to be dangerous as a villain. She can manipulate anyone and get people to follow her without them knowing that she is simply pulling strings. She is also good in a fight, and while it seemed Bumblebee took her out with that final blast, there is always a chance that she is still out there and just let him think he had defeated her. While Michael Bay's movies are on hold, there is still a chance Quintessa could return for a second round in the future.

1 Unicron

The most powerful being in existence, Unicron is the most dangerous and deadly villain to ever grace the Transformers universe. Cosmic in size, his alternate form is an entire planet and is able to destroy entire worlds with virtually no effort. Unicron's main goal is simple enough: to destroy the very fabric of existence and become the only being left alive. Unicron is not only able to easily travel between universes but even appear in different realities. Unicron has created other beings to support his goal and is remorseless in his destruction of the multiverse.

While fans got a glimpse at Unicron in Transformers: Age of Extinction, he finally arrived in all his might and glory in Transformers: Rise of the Beasts. With his army of Terrorcons, he destroyed an entire world where the Maximals lived, and few escaped from his attack. Unicron is a massive being and he has destroyed countless planets and worlds, and could have destroyed Earth if the Autobots had not defeated Scourge and closed off the portal that he was planning to travel to. There is no telling how he will eventually fall in the movies, but right now, there are no bad guys in Transformers deadlier than Unicron.