The Mass Effect universe is populated with a dazzling variety of alien races and unique individuals. It's a dangerous galaxy out there -- especially in the lawless Terminus Systems. As such, some aliens have trained to become the ultimate soldiers, assassins, or powerful biotics. Commander Shepard will meet, recruit, or fight against many of these powerhouse characters.

RELATED: Dragon Age: 10 Most Powerful Mages, Ranked

As of the series' beginning, when the SSV Normandy SR-1 is approaching Eden Prime for Shepard's first mission, who are the most capable soldiers and fighters in the galaxy? At this point, many of Shepard's squadmates have not yet reached their potential. In ME2 companion Grunt's case, they haven't been born yet. Instead, other characters are the galaxy's most powerful fighters and they won't go down easy.

10 Nihlus, The Noble Turian Spectre

Mass Effect Of Screenshot Nihlus

Fans saw very little of Nihlus during the Mass Effect trilogy, but his reputation and his rank speak for him well enough. This Turian warrior is a Spectre -- one of the elite agents of the Council and that fact alone speaks volumes.

Even with hostile Geth all over Eden Prime, Nihlus was perfectly capable of operating alone; in fact, he worked better that way. He also once fought Samara, a powerful Justicar, and broke even with her. Not just anyone can escape a Justicar like that, but Nihlus did it through firepower and guile alike.

9 Zaeed Massani, The Blue Suns Veteran

Mass Effect 2 Screenshot Of Zaeed Loyalty Mission

Mercenaries are a vital part of the Mass Effect galaxy and some groups have made a real name for themselves such as the Blue Suns. Zaeed Massani co-founded the Suns with Vido Santiago and, after he was betrayed and left for dead, Zaeed went his own way.

Zaeed's extensive experience, nerves of steel, sharp aim, resourceful mind, and pragmatic streak all make him a highly effective mercenary. He's pulled one stunt after another, such as torturing and killing a Krogan warlord, crashing an entire Turian frigate, and far more. By the time he joins Shepard's team as a companion, nothing can surprise him.

8 Matriarch Benezia, Legendary Biotic

Mass Effect Matriarch Benezia Using Biotic Powers

Through the events of the first game, it is revealed that Matriarch Benezia is Liara's mother. She is also one of Saren's primary generals in his unwitting plot to achieve Sovereign's goals. Furthermore, she happens to be one of the oldest and most powerful Asari biotics.

RELATED: The 10 Strongest Women in Fire Emblem: Three Houses

While not much is shown about her abilities, Shepard faces off with her in an epic battle. Let's not forget that she also helped clone and resurrect a queen from the previously extinct Rachni race. Without her helping him, Saren surely would not have gotten as far along as he did with his plans.

7 Jack, Patient Zero

images of Jack from Mass Effect 2 and 3

At this point in the story, Commander Shepard had not yet met Jack the powerhouse biotic. But she was out there wreaking havoc and stealing what she needed to survive. Jack had been experimented upon at the rogue Teltin facility -- a peripheral Cerberus base. She eventually escaped and went on a rampage with her insane abilities.

Jack's biotic powers are highly advanced for a human and she is never afraid to use them. Jack is also opportunistic and street-wise in many ways which allows her to outmaneuver her enemies or escape a dire situation. She is not someone to be trifled with.

6 Urdnot Wrex, The Krogan Hitman

urdnot wrex mass effect

Urdnot Wrex, like Zaeed Massani, was already an experienced veteran by the time Commander Shepard embarked upon the Eden Prime mission in 2183. Wrex once dreamed of uniting the Krogan, but he soon went his own way and sold himself out as a mercenary (as many Krogan tend to do).

Wrex doesn't really have a unique twist on this idea; he's simply a very tough, street-wise, and ruthless mercenary. He knows when to pick fights and when to cooperate with other people. But that's all for the sake of a job, of course; he's not doing this to make friends. Ultimately, he's looking out for himself, but he can develop a great rapport with Commander Shepard. Or not.

5 Saren Arterius, The Rogue Spectre

Mass Effect Screenshot of Saren

Saren Arterius is a Turian Spectre just like his friend Nihlus, but his methods are rather different. Saren takes full advantage of his operational freedom as a Spectre. This often means brutally executing his enemies, allies, and bystanders alike as the mission dictates. He is crafty and cunning as he is able to quickly read and adjust to any situation.

RELATED: Mass Effect: Commander Shepard's 5 Most Dangerous Side Missions (& 5 Easy Ones)

All of this makes Saren quite dangerous to his enemies and, by 2183, he was already an ally of the Reapers with high-tech Reaper implants in his body. After facing Commander Shepard on Virmire, Saren gets yet another upgrade and becomes a true cyborg.

4 The Thorian, Plant-Based Mind Control

images of Shiala, the Thorian, and creepers from Mass Effect 1

This creature is an enigma even to this day as nothing like it has appeared in Mass Effect lore since. Sure, the mysterious Leviathans come close in terms of mind control, but they also developed inorganic technology. The Thorian relies entirely on organic-based innovations and evolutions.

Shepard encounters the odd ancient creature and its "creepers" on Feros. The Thorian has even co-opted an Asari Commando named Shiala to be its voice. The organism somehow survived the Reapers, but Shepard put it down for good (it appears).

3 Thane Krios, The Drell Assassin

thane mass effect

Many of the galaxy's most dangerous agents are assassins -- trained to stalk and eliminate a target by any means necessary. The best in the business is a Drell agent named Thane Krios who has been preparing for this line of work since age six. This might sound like he had a troubled life, but with the way Drell culture and history are, it makes sense.

RELATED: 15 Games To Play If You Like Mass Effect

Thane's body can move on autopilot, acting without remorse, fear, or hesitation. In fact, Thane has unique assassination moves in mind for a target of any species. He can move so fast that the naked eye cannot follow him. And, of course, his martial arts skills and aim with a pistol are astonishing. Thane executed most of his contracts before ever stumbling upon Shepard.

2 Samara, The Justicar

Mass Effect 2 Samara During Her Loyalty Mission

Samara combines many key elements to become the galaxy's most formidable fighter of all. She is an Asari, giving her powerful natural talents for biotics and, even by Asari standards, Samara is quite powerful. She has been fighting for centuries -- long before humanity even put Sputnik in space.

In addition, Samara is a well-trained Justicar -- a sacred, but nomadic agent who dispenses justice by gunpoint at her discretion. Her mere presence is enough to scare off pirates and raiders before they fire a shot. As Shepard eventually saw, Samara can take on a whole squad of elite Eclipse troopers and slay them all without taking any return fire. Now that's impressive.

1 Sovereign, The First Reaper

images of Sovereign from Mass Effect 1

This moniker is a bit deceiving as Sovereign is, by no means, the first Reaper. Fans will remember that the Reaper cycle happens every 50,000 years and has been ongoing for millennia. But Sovereign was the first Reaper with whom the Milky Way species had contact.

He used the Reaper indoctrination to take hold of two very powerful people: Saren and Benezia. Wielding them as puppets, he nearly destroyed the Citadel and, depending on player choices, can kill the Council. He was the biggest ship in Saren's fleet and far bigger than most ships possessed by any race at the time.

Next: 10 Hidden Details In The Next-Gen Mass Effect Trailer You Missed