Content Warning: major spoilers for Marvel's Eternals are discussed in this article.
Marvel's Eternals has finally released and with it introduced a new team of superheroes from the comics into the MCU comprising of a varied cast of characters. Each member of the Eternals has their own particular set of characteristics that complement each other and the team as a whole.
Ajak serves as the Prime Eternal and leader of the team on Earth; Ikaris, Gilgamesh, and Thena are the ones most focused on combat prowess; Phastos is an expert on technology, and so on. While each one of them works best as a unit and no single Eternal would likely beat the rest as a group, they individually have a relatively firm place in a power hierarchy.
Sprite
In the fight against hostile Deviant aliens, Sprite would likely be the weakest of Eternals, though, she certainly has her merits to complement the rest of the team in action. The likes of Ikaris, Thena, Gilgamesh, and Kingo definitely outclass her physically, but Sprite's eerily life-like projections can help the group gain evasive advantages.
The Deviant attack in present-day London showed how she could buy Sersi and Dane Whitman time to get out of dangerous situations by confusing the attacker. Members like Sersi, Phastos, and Ajak have more proficiency in their support abilities in combat situations, but having Sprite helps by having more numbers providing backup in battles lasting generations against the Deviants.
Phastos
In the Eternals team, comic book fans know that Phastos serves as the technological brain first and foremost. His tremendous intelligence helps with things like weaponry as well as designing advancements to help contribute to humanity's evolution. This can help everyone out on the field, but the limitations Phastos is forced to abide by clearly show his potential has yet to be reached.
The technology he's capable of designing and building on such short notice is impressive, to say the least. Particularly so when he was shown able to use some of his inventions to greatly restrain someone as almost insurmountable as Ikaris in the final act of the movie.
Makkari
The primary ability that Makkari has could be comparable to Sersi's in its supportive nature. She's capable of superhuman speed that looks to be on a similar level to DC's Flash. In Eternals, fans see her ability used exceptionally well in damage-control situations.
Makkari is able to near-instantly evacuate dozens of people out from dangerous situations and clear the way for the team to defeat the attacking Deviants. While combat isn't her specialty, she did show that she can be effective at quick hit-and-run attacks as a backup like in the remaining team's collective fight against Ikaris to stop the Emergence.
Druig
Druig is definitely one of the most complicated heroes within the group, as he's hard-headed and difficult to reason with once he takes a stance on something, but he arguably has one of the most useful powers. His ability to control peoples' minds -- even on a mass scale -- mostly makes up for his lower proficiency in direct combat compared to Thena, Gilgamesh, Ikaris, and Kingo.
It's a potentially terrifying ability had it fallen to someone else since it could easily be abused for nefarious purposes. However, his compassion for humanity and Druig's quote towards the end of Eternals spotlights his growth and maturity.
Sersi
Sersi also provides an important supportive role for the Eternals even if her power in combat isn't the highest. This importance is proven in her ability to manipulate inanimate objects through touch to turn them into something else. The beginning sequence in London where Sersi transforms the bus flipping over into flower petals -- while saving those inside it -- is one of the best showcases for this power.
Given that Arishem's primary design for the Eternals is to protect humans, her abilities are invaluable for support and damage control. In terms of mental fortitude, she's on track to reach the heights of Ajak as the team's central pillar morally and tactically. Her potential power ceiling is high, and Ajak choosing Sersi as her successor is proof of this.
Ajak
The Prime Eternal of Earth Ajak isn't one of the Eternals strongest when it comes to fighting on the front lines, but with her role in the group, she's proven more than capable of holding her own. Ajak's most prominent power is her impressive healing/regenerative abilities, which greatly bolsters her survivability and emphasizes her importance to the Eternals.
This ability and her role as the moral and strategic center of the team match her title as Prime, especially given Arishem designed her with this in mind to ensure they all stay cohesive as a unit. Her immense capability for empathy and the maternal figure Ajak also serves as proves invaluable for the likes of Sersi, Phastos, Druig, and Makkari to challenge Arishem's grand design and stop the birth of the new Celestial.
Kingo
Kingo doesn't match the strengths of Ikaris, Thena, or Gilgamesh, but he is arguably the next most powerful in terms of physicality. His physique and abilities are up to par to fight Deviants head-on, which he demonstrates against Kro and his cavalry during the fight in the Amazon.
That scene showed he's capable in both close quarters and from long distances since his physical power is complemented by the cosmic projectiles that he can fire. The Deviant he killed also showed how incredibly agile he can be.
Thena
Though Thena's mental state is one of the unanswered questions that Eternals leaves behind, her level of power is indisputably among the group's highest tier. She became the basis for Earth's Goddess of War, and her enhanced strength and ability to conjure a weapon and shield at will are testaments to that.
In addition to Gilgamesh, Thena's one of the few who would be able to stand against Ikaris in a one-on-one fight. Thena's power is also shown in how dangerous she could be when afflicted by the Mahd Wy’ry illness, which erodes her memories and becomes violently erratic due to having been alive for so long.
Ikaris
While he's canonically outclassed by one other, Ikaris would likely be the second-strongest of the group in terms of raw power. Director Chloé Zhao based this iteration of the Eternal off of Henry Cavill's Superman to combine the sheer feats of strength he's capable of with an internal moral conflict.
Once he reveals his hidden motives after spending so much time hiding the truth Ajak told him, effectively turning him into a villain, it becomes clear it takes a daunting amount of force to bring Ikaris down. Gilgamesh's death left a power vacuum and only Thena was left who could at least closely challenge him on physical prowess, but it's ultimately the remaining team effort that finally stops him from completing the Emergence.
Gilgamesh
Gilgamesh is regarded as the strongest member of the team. He's a powerhouse using optic blasts from his fists with all the other boons that an Eternal has, i.e. ageless and superhuman physical strength. Gilgamesh was key in (initially) wiping out the Deviants from Earth, and even holds his own respectively against the resurgence of the evolved wave of them.
He does eventually succumb to his wounds after the new, lead Deviant Kro ramped up its own strength by absorbing the Eternals' power, but its newfound strength is something alien to the team scrambling to stop them. All the while he was trying to fend Kro off while protecting Thena. Similar to Ajak, another key strength of his is his incredible degree of composure under pressure and compassion.