Okay. Take a planet. Now make it entirely artificial. But not made out of metal beams and such, made entirely out of trillions of Sentinels linked together. Then, at the center of the planet you have a portal. Take a step through the portal. You are now in a slipspace bubble the size of a person. However, that's not what you see since you're inside of it. You look around. There's a star about the size of our star. Surrounding it is an inverted planet that you are standing on. Where you're standing is the same distance the Earth is from the sun. You are inside a Dyson sphere. You start to explore. You encounter more portals that lead to more realms held by slipspace and compressed to a very small size in real-space. Time passes slower in slipspace. The deeper you go onto these realms, the faster time goes by in realspace compared to what you're experiencing. And that is Onyx.