The Gatewatch/Visions and prophecies

The story of the Gatewatch was mapped out in the Bolas Arc. This allowed the writers to weave in some visions and prophecies that would come true in later chapters. It is expected that eventually all elements of the prophecies will come about.

Nissa's visions

On Amonkhet, Nissa Revane experienced several visions sent by Kefnet in The Hand that Moves.

Vision	Event
A dark snake, winged and venomous, cast its shadow upon the desert. The snake was huge, bigger than an oak, bigger than a forest of oaks. Its shadow covered the whole world.	Nicol Bolas, arriving on Amonkhet to take control of the plane.
The shadow spoke, its voice rumbling across the empty desert. "They would take away my power. They would take away what makes me me. This I will not abide.	Bolas voices his outrage at the efforts of other planeswalkers to seal the time rifts, bringing about the Mending and taking away his god-like power.
The shadow of the snake wrapped its coils around the world. "For what I require, I would drain every world. I would devour every single one. But I start here." The shadow squeezed. The world screamed.	Bolas attacks the worldsoul and the leylines of Amonkhet.
She was looking up into space, into the stars. Eight stars. Eight stars in a loose circle and evenly spaced, lighting up the entire night sky.	The original eight gods of Amonkhet.
A line of darkness, somehow visible even against the night, a line that shone darkness, wove its way through the eight stars. The line twisted and turned and vibrated, its pulsing a violent cry. When the line ceased moving, it was a figure eight on its side, a snake eating its own tail. It encompassed all eight stars, each star twinkling desperately against the curtain of dark now nestled close against them.	Bolas attacks the gods.
Three of the stars winked out. Their generation of light and heat snuffed. Their lives vanished.	Three gods succumb and are forgotten.:
But Nissa could still see movement where those three stars had been. Stars no more, just three dark rents in the fabric of the sky. Three dark holes, possessed of an energy and fury all their own, pulsing to a rhythm malevolent.	Bolas turns the three forgotten gods into The Locust God, The Scarab God and The Scorpion God.
The five remaining stars moved, their new alignment warped, all bending to the shadowy line woven through their constellation. Their new outline suggested a pair of horns.	The five remaining gods are twisted into serving Bolas.
Awkward figures wrapped in white linen bent and dug in the harsh sands. Mummies, they called them. The anointed. Hundreds, thousands of the mummies dug into a deep pit, pulling out a blue ore. Cartloads of the ore snaked their way in a large procession toward the city.	The anointed mine lazotep for Bolas.
Farther away, three young children stopped before a barrier. The beautiful city on one side, the stark emptiness of the desert on the other. They're whispering to each other. They look around, look at each other. Uncertain. A child presses through. The two others follow. All three are swallowed by the hungry sands.	Samut, Djeru, and Nakht pass through a small hole in the Hekma, venturing into the deserts beyond Naktamun, and discovering old, crumbled structures from before Bolas invaded. Nakht actually dies to a horror of the sands. Samut is "swallowed" by grief and doubt from Nakht's death and seeing the ruins and the symbol for "Trespasser" on them. Djeru rejects what he has witnessed, devoting himself to the Trials.
She saw a young man, his face erased, stumbling among a garden of statues. High above the man a growing cloud of dusk attacked the sun. From somewhere outside the garden there was a mighty roar.	Jace Beleren, his memories erased, arrives at Orazca on Ixalan, where the Immortal Sun is encased in the temple. Bolas's influence is growing on this plane, as well. Zacama, the a living embodiment of the Threefold Sun, roars in protest.
Nissa saw a world, then tens of worlds, hundreds of worlds. Thousands. She saw this world, the world of Amonkhet, and wrapped around it was a dark sinewy line. That line stretched back through all the worlds, all the thousands of worlds, and she saw an unbroken line of darkness from Amonkhet all the way back to the beginning of the line.	The "plots that span centuries" that Bolas has woven throughout the multiverse, stretching back to his birth on Dominaria.