It takes thousands of years for the Expansion to become anything other than a grey mass where planets once stood.

Ego doesn't mind. It's worth the wait when he sets out onto one of his many worlds, feels the roots growing in fertile soil and sees green and red petals emerging from the earth. He caresses a small leaf in his hands and closes his eyes, feeling the thrum of his and Peter's souls pulsing beneath the planet's crust. If he reaches out further, he can hear that beating heart echo throughout the universe; the fruits of his labour filling him with a warmth and satisfaction he has craved for as long as he can remember.

It is a shame the boy cannot be here to see these glimpses of life first-hand. Peter remains strung up like a rag-doll after all these years, despite Ego's best efforts to convince him to partake in the Expansion voluntarily.

There's nothing he can do about that, though. The boy will not help him. Even now, rage and hatred burns behind green eyes on behalf of the friends he lost, but Ego's influence on the universe cannot be maintained alone. He needs Peter - needs the power that flows within him - and he can't afford to be picky over the means through which he acquires that power.

Ego has given Peter so many chances to make things easier. He has offered time and time again to let him down from the tendril and train him to use his power properly, but though the boy says not a word, his rejection burns like fire. Any attempts to make being strung up more bearable have similarly failed; Ego has lost count of the times he's lulled Peter into the peace that comes with seeing eternity, only for the stars in his eyes to stubbornly be replaced with Meredith's green.

"So be it," he growls every time, before leaving Peter to be drained for a further hundred years. If he's feeling kind, he'll take a moment to rest a hand upon his son's face and wipe a stray tear from his cheek before walking away.

There's a nagging sensation in his chest every time he abandons his son to wander among the stars. A loneliness he had hoped would vanish upon the discovery of a child who shared his celestial blood.

It is no matter. So long as the Expansion's completion awaits, he will always have meaning to satisfy him.

Even if the company of another cannot.

The Expansion, once complete, is truly as beautiful as he could have hoped.

Ego walks side-by-side with his son across a planet littered with crimson leaves, while the trickling of streams flowing into shimmering pools fills the air. There is no other sound – no unworthy life-forms to disturb the peace – and he smiles as he takes in the sights and fresh smells, feeling the planet's core beating beneath his feet. There are so many worlds like this one now, his influence stretching further than he could ever have imagined, and Ego turns to Peter in the hope that he will show even a fraction of the pride that now flows through himself.

He doesn't.

The boy looks empty, with his green eyes focused only on the leaves beneath his feet and his brow furrowed with pain he should have gotten over millennia ago. It's starting to become irritating, how he'll refuse to say a word and hide behind blank stares even when presented with everything they've achieved together, and Ego's starting to wonder if the boy prefers being drained like a battery over his freedom.

Peter's catatonic act does little to fool him. Every time he tries to plant eternity into the boy's mind to calm him, a barrage of thoughts will respond without fail; pushing him away. There must be something hiding behind that mask.

Ego chooses to ignore his son's silence and continues walking with a hand wrapped around his forearm.

It is the only way to make him follow.

"I remember telling your mother about all this," he explains as they make their way across a forest floor, stepping over twisted roots and green vines. He can't help a bitter smile from forming when he feels Peter tense beneath his grip. "She thought it sounded beautiful."

And she had. Ego hadn't been entirely truthful about his intentions with her – going more for an explanation that suggested creating worlds from scratch rather than converting pre-existing ones to his design – but her eyes always lit up when he described all those planets connected to his very soul. What she would have thought of him had she known the truth, he cannot say, but had she been as immortal as her son perhaps he could have convinced her that this was for the best.

Then again, perhaps not. The stubborn streak coursing through Peter is Meredith's own, and it has not let up for millions of years.

When he turns to look into his son's eyes, he's almost relieved to see some life flashing within them, even if that life brings hatred with it. It burns fiercely behind a green he once dreamt of returning to (before he'd done what was necessary to ensure he never became tempted to settle on Terra), but the boy is smart enough to know that striking out will do nothing. Ego cannot be hurt, so long as his light continues to flow through all the planets in the universe, and Peter with his so-called 'Guardians of the Galaxy' had failed to destroy just one.

As they return to the ship which will return them to that very first world – the one Ego still calls home after all this time – he takes his son's hand and ignores the flinch that comes with doing so.

"One day, you will see the beauty too," he promises.

He knows before the words leave his mouth that it's a lie.

Ego takes no pride in watching his son suffer. He has done everything in his power to make his stay comfortable; has offered time and time again to let him down from the light, on the condition that he co-operates for once. And yet, even now, he continues to be shot down and refused by his own child, and is forced to leave him in pain and exhausted from having his energy sapped for the Expansion's benefit. It's a shame his anger forced him to destroy the boy's Walkman all those years ago; perhaps that would have provided him with some small comfort in his loneliness.

It might even have given Ego something to focus on, to distract from the returning sense of something being missing and the emptiness that Peter's silence has caused. The Expansion was completed millions of years ago – now only needing their input for maintenance - which means he's suddenly found himself with a whole lot of time to linger on the fact that that brief, wonderful satisfaction has long since deserted him.

It's almost enough to make him miss Mantis. He cannot remember when he last slept, and the ability to dream of something pleasant is one he craves.

She could have helped Peter sleep too and eased Ego's conscience about his circumstances, though if the boy has the power to reject glimpses into eternity then it is likely he'd have rejected the girl too.

Ego learns to content himself with travelling alone - the novelty of showing his child their masterpiece having worn off - and tries not to dwell on the fact that, as beautiful as his creation remains, everything is starting to look the same wherever he goes.

He tends to forget that Peter is half-Terran. The joy at knowing that one of his progeny shares his celestial genes is one that has clung to him for so long, it is easy to forget the inherent weakness present in his son's biology.

That's why it takes such a long time to comprehend what he's seeing when, without warning, the blue tendril of light now permanently embedded in Peter's chest sputters before vanishing completely, dropping his son inelegantly to the floor. There is no more power to be drained – nothing more Peter can offer him – and all that's left flowing through his veins is mortal blood.

How disappointing.

He cradles the boy in his arms for the hours it takes his heart to give out, but Peter continues to pay him no heed. Instead, glassy eyes linger on something Ego cannot see and a single tear slips down the side of his face, before an absent smile forms and a broken "Mom?" passes his lips.

It's the first word Peter's said in a billion years.

He doesn't say anything else.

Ego remains silent too, trying to be delicate with his son though there is no longer a need to do so, but, though the expression on his face never alters, he can distantly feel thousands of planets imploding from his rage.

He buries his son on the crimson planet that was once Terra. It's the least he can do.

The sun burns hot at his back and sweat drips down his neck as he digs with a spade he fashioned himself, deliberately avoiding the easy route of simply letting the earth swallow Peter as it had his other children. The work does him good – distracts his mind from the loneliness which has returned as a dull ache – and the presence of a glowing blue root nearby is enough to reassure him that he's returned the boy to his home.

Meredith will be here too, somewhere close by. It's the closest he's been to her since that final, hurried meeting where he left her with a chaste kiss and the beginnings of a tumour in her head. It's a good thing her planet no longer looks the way it once did otherwise he may not have been able to return at all, even for the sake of their child.

It is foolish to miss her after all this time, he knows, but that doesn't stop him from lingering by the root he once showed her in the moments after his son has been committed to the ground.

Peter's death is… troubling, to say the least. Already, Ego can feel the fabric of his worlds start to splinter under the weight of the boy's absence, and though he is powerful, the truth remains that one celestial is not enough to maintain something as ambitious as the Expansion. His flight home shows red leaves beginning to turn brown with decay and once-rich pools starting to dry up under fierce suns; the effects spreading like a disease throughout every planet besides the original.

No matter. If becoming everything in the universe was not enough to bring him satisfaction then there must be something else. The slow deaths of those worlds are no loss.

Peter, on the other hand…

The boy may have been poor company, but there's a vital difference between feeling lonely and truly being alone. The universe hasn't been this empty since Ego's inception, when his only companions were confusion and pain.

He will need to find something else to fill the hole that lingers within him, and soon.

The answer comes to him quickly, and it takes little time for him to act upon it.

The decay of his Expansion need not be a slow one, he decides, as he flies across the universe and one by one cuts himself off from each world he passes. The separation feels like a dull knife removing a limb from his body, but it is worth it to see the beauty of entire planets crumbling into red and green and blue fragments before spreading throughout the cosmos as stardust.

It is a sight Peter would likely have found bitter satisfaction in, but Ego pushes that thought from his mind.

Over centuries, he travels and watches as his failures dissolve into something beautiful and the sight brings a smile to his face every time, even as the numbing emptiness becomes more difficult to ignore.

He hesitates on only one occasion; upon finding himself staring down at what was once Terra. Her crimson leaves have been reduced to brown skeletons and the once-glittering blue of her oceans has faded. It was Peter who kept her beautiful all these years, but with him gone there is nothing worth saving on that rock besides the bodies of Ego's son and the woman he loved.

Their memory is not enough to stop him from cutting ties with Terra's core and watching her crumble into stardust.

By the time he returns to his own planet, it is the only thing that remains. His goal has been met and he returns to the place of his creation as the lone survivor of the universe; the Apex predator that consumed all else.

He is the only thing in existence. Everything that matters is made of him.

Ego sits on his golden throne, the core of his planet burning as brightly as it always has, and clings to the hope that he has finally found the meaning he has been searching for.

The hope that, finally, this is enough for him to be satisfied.

(It isn't)

A/N - I'm in two minds about Ego. As much as I hate him, I can't deny that he's one of the most interesting villains in the MCU and Kurt Russell plays him brilliantly (even more noticeably so on rewatches), so I couldn't ignore this idea when it started to form in my brain. I hope you enjoyed this and any feedback is appreciated!

The title is lifted from Muse's piece of the same name, while the story itself was partly inspired by the latter half of their song 'The Globalist' (because that band acting as a literal muse for me seems to be a constant in my life :P )