Agents of S.H.I.E.L.D is the longest-running and most successful Marvel TV show. With five seasons under its belt, Phil Coulson and his team of agents have been everywhere and seen everything, from regular thugs and goons in America to robots, superhumans, and aliens on distant planets. Needless to say, this loveable squad has racked up a rather large list of enemies over the years. Some were easily dealt with and proved to be nothing other than distractions for the team. Others, however, proved to be so powerfully destructive that some meaningful lives were lost — some even having to be sacrificed. With that said, here are the 10 deadliest Agents of S.H.I.E.L.D villains, ranked.

10. Ruby Hale

One of the last remaining HYDRA agents along with her mother, Ruby was genetically engineered by Daniel Whitehall to become the perfect future leader of HYDRA. After the evil organization fell, she continued to train with her mother to fulfill her life-long dream of being fused with Gravitonium and becoming the immensely powerful Destroyer of Worlds.

Ruby Hale is shown to be a skilled, cold-blooded killer, yet selfish and immature. Like the stereotypical teenager, she's prone to acting based solely on her emotions. This unpredictable nature combined with her deadly skills makes a very dangerous foe and is what ultimately leads to her death.

9. Katya Belyakov

Katya Belyakov is Marvel's portrayal of a demon child. A girl who underwent Terregenesis at a very young age and was driven insane when she was then granted with Inhuman powers. Most people don't know her name but know her as "the little girl in Bahrain" that Melinda May was forced to kill even though it traumatized her.

Katya showed her true evil nature when she did not hesitate to use her mind-controlling powers to make others to terrible deeds for her, before killing them herself. Although her evil acts were short-lived, her death impacted Jiaying's fear of S.H.I.E.L.D, and ultimately the war between S.H.I.E.L.D and the Inhumans and (as extreme as it sounds) it stopped HYDRA from ruling the world, as shown by the alternate world of the Framework.

8. John Garrett

Season one spent the entire time setting up a mysterious evil mastermind named The Clairvoyant. It then later introduced us to John Garrett, a likable, high-ranking S.H.I.E.L.D agent and longtime friend of Phil Coulson. When HYDRA was revealed to have been infiltrating S.H.I.E.L.D all along, Garrett showed his allegiance to Hydra and his identity as The Clairvoyant. Besides his excellent combat skills and his cybernetic enhancements, Garrett was also responsible for creating the infamous Centipede Project and, most importantly, raising Grant Ward, making him the traitorous cold-blooded killer we all know. Luckily, Coulson managed to put an end to Garrett's life.

7. Daniel Whitehall

After the fall of S.H.I.E.L.D and the death of HYDRA leader Alexander Pierce in Captain America: The Winter Soldier, Daniel Whitehall was chosen as his replacement. Besides Red Skull, Whitehall might have been one of the most influential members of HYDRA.

He found many mysterious artifacts (including the Obelisk) during World War II, tortured and cut up the Inhuman leader Jiaying to achieve eternal youth, became the leader of HYDRA 70 years later, mentored Gideon Malick, Wolfgang von Strucker, and General Hale, brainwashed several people, and was mainly responsible for Daisy's and Raina's Inhuman transformation.

Needless to say, we were all very glad when Phil Coulson stepped in again to kill him.

6. Graviton

General Talbot as Graviton in New York in Agents of Shield

For most of the series, General Talbot was either a thorn in the agent's sides or a reluctant ally, but he was never a deadly foe. That is until season five, where his mentally unstable persona decided to enter the Particle Infusion Chamber and infuse himself with all the Gravitonium they had.

This gave him incredible gravity-manipulating powers. Although he appeared to be on the heroes side at first, the experiment made him even more unstable, and after learning of Thanos' invasion of Earth, he believed he alone had to stop him. This belief led him to kill Hale and to become a threat to everyone around him. If he hadn't been stopped by Daisy, he would've shattered the Earth in half...literally.

5. Kasius

Dominic Rains as Kasius in Agents of SHIELD

The only alien on the list. When Coulson and his team traveled to the future, they found Earth nearly completely destroyed with a Kree, Kasius, ruling over what remained of it. Like most Kree in the MCU, he was nothing other than evil and thought of humans as inferior creatures, treating them like slaves. Between ruthless, random killings, torturous acts, and his overall disgust towards human beings, he was clearly a terrible ruler. It only got worse as he grew tired of his job and sought to collect enough money to be able to kill what was left of humanity and escape. As is excepted when going up against the Agents of S.H.I.E.L.D, Kasius' plan, along with his life, was destroyed.

4. Jiaying

Jiaying was an Inhuman with the power of stealing people's life forces. She was a kind and caring woman turned ruthless villain after going through a series of traumatic events. If being cut to pieces by Daniel Whitehall wasn't enough, she then returned to life after being stitched back by her husband. When they returned to their home, however, they were horrified to find that their baby daughter had been taken by S.H.I.E.L.D.

These experiences gave Jiaying an intense hatred of humans, which she then incorporated into her life by attempting to rid the world of all humans while Inhumans remained. After a complicated relationship between the evil mother, the violent father, and Daisy, it was the father who stopped her madness.

3. Grant Ward

There would be no villains without Grant Ward, the only one on the list who is 100%, all-natural human. Ward's journey from a typical dull action hero, to a deeply disturbed, merciless foe is an incredibly tragic one. His initial HYDRA reveal was one that no one saw coming and suddenly made him a very unnerving character.

Although never succumbing to the standard rule-the-world objective, he spent two and a half seasons inflicted pain, death, and destruction to those who opposed him, including the team (and the girl) he once loved. His combat skills rival those of the Black Widow and his ability to deceive others is uncanny. His ending was sad, yet fitting. He never completed any redemption arc, remaining evil right until the end. Instead, he was killed by the hand of his former leader and personal enemy, Agent Phil Coulson.

2. Aida

Since the end of season three, and throughout most of the following season, we were teased with the possibility of the "AI turns evil" story making its way to Agents of S.H.I.E.L.D. And it did. When Aida was introduced, it looked to be a sign of bad things to come, but suddenly she evolved from assistant to hero, saving Coulson, Fitz, and May in the process.

It seemed like Marvel had isolated themselves from that common trope until Aida was corrupted by the Darkhold, taking nearly the entire team and imprisoned them in the Framework, became the leader of HYDRA, came back as a human, and tried to kill the entire team who had miraculously escaped from the Framework.

So yes, they did go down the evil AI route, but it worked, making Aida (or Ultron 2.0) one of the shows most dangerous villains.

1. Hive

Nothing is as deadly as when you combine every single villain into one perfectly evil being. Hive sought to rule the world (like HYDRA), transform everyone into Inhumans (like Jiaying), lacked empathy and was cool and controlled (like Aida), and had excellent combat skills (like Ruby). To top it all off, he walked around in Grant Ward's healthy dead corpse.

NEXT: Agents of SHIELD: Clark Gregg Is Playing 'Not Phil Coulson' In Season 6

Hive was one of the first ever Inhumans, and possibly the most powerful. His ability to possess human bodies meant he could never die. That, plus his mind-control powers made him pretty much unstoppable. How do you stop a villain who can't die? By blowing him up in space, that's how. Hive was also the reason HYDRA was created, as the organization's initial ancient plan was to bring him back to Earth after his banished to a distant planet thousands of years ago. He returned but was obviously stopped in his tracks by the Agents of S.H.I.E.L.D.