Hey OP, I've been hearing of this cool place called the warp where these two combatants should fight.
The warp is the multi/omniverse(or is connected to them)"The forms the live-things called Chaos, in their limited little ways of perceiving the omni-verse, swarmed and thrived in this infinite ocean of mind and emotion. The daemon moved with Stele. Waiting, waiting and watching for the moment when the thrashing and chattering of the quarry was at its peak. Only then would it strike, lapping up the absolute perfection of its fear, sinking in rending teeth, tearing it to soul- shreds."
Pg.106 Deus Sanguinius
“A miss indicates that the missile has left Warpspace at the wrong point – and this could be anywhere in any of the million universes.”
pg.37 Adeptus Titanicus
Thoughts can destroy or create thousands of universes in the warp
"Here in the Great Ocean, he could be whatever he wanted to be; nothing was forbidden and anything was possible.
Worlds flashed past him as he hurtled through the swelling tides of colour, light and dimensions without name. The roiling chaos of the aether was a playground for titanic forces, where entire universes could be created and destroyed with a random thought. How many trillions of potential lives were birthed and snuffed out just by thinking such things?"
Pg.712 A Thousand Sons
Chaos is older than time
All around him, he could hear the sounds of the future, of warfare and death. The thought that he shared the guilt of the destruction of the Emperor’s dream was the greatest shame and sorrow he had ever known.
An end to it all would be a blessed relief.
‘Oblivion,’ he whispered as he closed his eyes. ‘Do it. End me.’
The barriers in Fulgrim’s mind dropped and he felt the elation of a creature older than time as it poured into the void in his soul. No sooner had its touch claimed his flesh for its own than he knew he had made the worst mistake of his life.
Fulgrim screamed as he fought to keep it out, but it was already too late.
His consciousness was crushed into the dark, unused corners of his mind, forever to be a mute witness to the havoc wrought by his body’s new master.
One moment Fulgrim was a primarch, one of the Emperor’s Children, the next he was a thing of Chaos."
Pg.757 Fulgrim
Click to expand...
"A terrible, ageless scream of frustration filled the chamber, echoing throughout all the realms of existence simultaneously as a creature older than time was thwarted in its ambitions."
Pg.619 Descent of Angels
"All I can tell you is that the warp is beyond the comprehension of you or I, and things exist in its fathomless depths that are older than time as we know it.’"
Pg.359 Battle For the Abyss
Schrodinger's Slaanesh/Chaos
That is how events are viewed from the chronology of the material universe. In the Warp, things are different, for the Immaterium is not bound by linear time, and events do not occur in a strict sequence of cause then effect. As his rival gods reckon it, Slannesh has always existed in the Warp, and yet has never existed at all
-Codex: Chaos Daemons 6th Edition pg. 16
That is how events are viewed from the chronology of the real universe; in the Warp, things are different. The Realm of Chaos has no true time, and events do not occur in a strict sequence of cuase then effect. In essence, Slaanesh has always exsted in the Warp, and yet had never existed.
-Codex: Chaos Daemons 5th Edition, pg.7
The sheer mind-boggling impossibiliry of the Warp defies
explanation, and those who attempt to delve further into
understanding its ways inevitably slip into madness. Of the
little that is known is that Warp space does not conform to the
laws of physics as we know them.
-Warhamer 40k 6th Edition Rulebook, pg. 144
It is a hurning ocean of chaos, raw emotion and madness given form, where the laws of physics, time and nature are meaningless concepts and nothing is as it seems.
-Warhammer 40k 4th Edition Rulebook pg. 122
In warp space there is no time, no distances, only a constantly flowing stream of immaterium.
-Battle Fleet Gothic Rulebook, pg. 85
It is a roiling, howling maelstorm of force and energy, utterly unpredictable and not subject to the rational laws and linear flow of time in the way that physical reality is.
-Horus Heresy Book 1: Betrayal, pg. 16
Beyond the boundaries of physical space, unrestricted by time or casuality, there is a dimension utterly incomprehensible to mortal minds.
-Codex: Chaos Daemons 6th Edition pg. 6
Beyond the boundaries of physical space, unrestricted by time or casuality, there is a dimension utterly incomprehensible to mortal minds.
-Codex: Chaos Daemons 5th Edition pg. 4
Timeless and ever-shifting, this psychic visionscape is known as the Realm of Chaos
-Codex: Chaos Daemons 5th Edition pg. 6
The Realm of Chaos, also known as the Warp, the Immaterium or Warpspace, is a dimension parallel to our own, a universe devoid of matter and life, without laws of time and space.
--Codex: Chaos Daemons 5th Edition pg. 6