The Celestials ordered them to ONLY help when
The team is mostly disbanded at this point. There's a reason Sprite asked who would lead them, because there isn't much of a team after Endgame. Currently, they don't have a headquarters, there isn't an active roster.
It was explained in the Eternals movie that the Eternals were ordered by the Celestial Arishem not to interfere in any conflict until and unless the Deviants were involved.
In the Eternals movie, Sersi said that the Eternals couldn't fight Thanos because they could only fight in conflicts that involved Deviants.
Technically, Gilgamesh and Sersi were the first Eternals from Earth to become members of the Avengers. But the first Eternal Avenger was none other than Eros, AKA Starfox. Starfox came to Earth in AVENGERS (1963) #232, and he immediately asked to join the roster.
In the Eternals film, it was stated that Thor knew who they were. Why does he let them help the Celestials destroy planets when Thor is supposed to be a protector? Most of the Eternals themselves didn't know their true mission until Arishem revealed it to them (except Ajak and Ikaris). Thor wouldn't know it either.
Now, it's not explicitly said in Eternals nor in any other MCU movie if Thanos knew about The Emergence in Infinity War or not, but he most likely did.
The Eternals may all have varying levels of power, but their strength as a squad is almost unmatched. Their immortality also gives them a huge advantage in battle, as it would take so much more force to take them down than would be necessary to subdue an Avenger.
An Eternal–Deviant warlord from the moon Titan, Thanos is regarded as one of the most powerful beings in the Marvel Universe. He has clashed with many heroes including the Avengers, the Guardians of the Galaxy, the Fantastic Four, the Eternals, and the X-Men.
Thanos, however, drew the shorter stick and inherited the Deviant gene, still diluted in the Eternals and capable of emerging from time to time. That's why Thanos looks like a giant purple guy; Thanos' Deviant gene deformed his appearance.
In an interview with Cinema Blend, the director said that since Eternals are synthetic beings who cannot be killed, their necks were saved during the massive snap by Thanos.
Sure, the winning outcome for the Avengers was the one where Tony sacrificed himself. But it was also the one where Thanos and Hulk's snaps had to happen because that's what led to the stoppage of the Emergence. The real purpose of the Eternals was to follow Arishem's design and allow the Emergence of Tiamut.
Thanos, however, is also afflicted by Deviant syndrome, a genetic disposition that gave him a monstrous appearance but also the power to synthesize cosmic energy, which made him stronger than most Eternals.
More specifically, they don't interfere with humans because their priority is the Deviants, the main enemy of the Eternals since their creation.
The Eternals also survived the Blip due to them being artificial and not biological beings.
Finally, Ikaris is definitely the strongest Eternal, and everyone else in the group acknowledges his powers. The fact that he is the only Eternal who can fly speaks volumes. On top of that, he has the physical strength to overwhelm the rest of the group combined.
Yes, as an Eternal, Thanos is immortal by human standards. Immortal meaning can not die by disease, or old age, as in natural causes. Thanos is NOT immortal but extremely long lived (much like Asgardians, he does age).
8 Gilgamesh Is The Physically Strongest Eternal
Most of the other Eternals have some kind of special extra ability, but Gilgamesh doesn't. His special ability is that he's physically stronger than the rest of them.
Peter Jason Quill was born in 1980 to Meredith Quill and Ego, making him a hybrid of human and Celestial. His conception was all part of a plot set up by his father to produce a second Celestial, whose power he could use to complete the Expansion, which involved assimilating millions of worlds into Ego's very being.
Wanda is theoretically stronger than anyone. Her control of her power isn't absolute and sporadic and her emotional issues can cause her to really lose control.
So, in the end as powerful as Eternals are, none of them would be too much for Thor, Hulk and Captain Marvel. Bring Doctor Strange and Wanda into the equation, and they don't stand a chance.
In the comics, Thanos and Eros are born on the Saturnian moon Titan to two Eternal parents, A'lars and Sui-San. Eros is born without the Deviant mutation, but Thanos is born with Deviant Syndrome.
First, the action choreography is dull, and the visuals are equally bland. Then there's the fact that there's nothing to strengthen most of the sequences; no emotional hook or character moments to be found. It ends up just being repeated scenes of super people punching bad guys.
Strange willingly gave the Time Stone to Thanos to save Tony Stark's life. He saw 40,000,605 possible futures and outcomes of the battle against Thanos. He knew that Tony must stay alive so they could come victorious ultimately and restore the universe as it was before Thanos's snap.