Rubicon

Rubicon is an endgame region exclusive to the Downpour DLC, acting as a counterpart to. is the only Slugcat that can access it.

Overview
Rubicon is an area unlike any other in the game, presenting itself as an amalgam of the Depths and all the other regions of the game, including those that no longer exist in the Saint's time like the Shaded Citadel and The Exterior. It is populated with extremely dangerous enemies and other hazards. The environment is dark, with glowing golden flecks and a dark red background.

Many of Rubicon's rooms are filled with Void Fluid that kills any non-natives on contact, including. Some of them have a tide effect that causes the fluid to rise up and fall down. A few rooms have the fluid flowing in inverse and pooling upwards. Some rooms have s in them, which block all connections to the room until ascended. Others have large gaps that require 's flight ability and tongue to navigate. Many rooms in Rubicon express other elements of the game, such as low gravity or flooded rooms. Some areas act as boss fights of sorts, requiring a Guardian to be defeated along with other enemies that pose a threat to the player.

Karma symbols in the background scattered throughout the area grant the max karma on contact.

Trivia

 * Some of the creatures and objects when spawned in Rubicon have a golden hue instead of their normal color. This has been seen with, Rot  , s, s, s. and s.
 * Rubicon has the acronym HR in game files, which stands for Hell Region. The region's early development name was Stygian Depths.
 * This is referenced in the last Saint challenge in the arena, as the challenge is named Stygian Depths. Likewise, the music that plays in the challenge is unique, and was originally intended to be the threat music for Rubicon, but was removed.


 * If the Saint ascends either, or both of them, they can be met one last time in the second-to-last room before the ending. Their dialogue varies depending if only one or both were ascended.

Ascending only Five Pebbles
I understand what you are, little beast. This place is not real, a dream from outside. As if every cycle of my existence has knotted together with another's, even if for only a fraction of a second it ripples through mine. I see my own creation, I see my agonizing decay. I see my hollow structure become a sanctuary in the storm. I see a new world unfold without me, as me. I see myself become something else. Yet... I cannot see the beginning, or end of your own. An aberrant cycle twisting into mine, before spiraling onward into the abyss. What a horrifying destiny you've found.

Ascending only Looks To The Moon
Little saint. I perceive your existence as it passes through my own. I know this is only a dream, but your presence is real. Do you see it too? Our endless repetitions, circling onward to infinity? From here I can observe the repeating loop of my own existence, every iteration a duplicate of the last. I have visions of the entire pattern my creators desired to escape at once. An endless sequence of life and death, further beyond my control with each passing cycle. Where does your cycle go, little creature? Its edges twist over themselves, like circles within circles, your cycle consumes itself. What have you become?

Ascending both Iterators
BSM: Do you feel it, old friend? FP: The sensation of time folding in on itself? The spiraling offshoot of another's reality wrapping around your own? BSM: None of this is real, is it? Every repeating cycle of our own existence unwound and laid bare, a cycle pulled into a tangent with itself. Is this what we were looking for? Have we broken free from it, or is it just a dream? FP: Was the answer always right there? Does the question mean anything to us now that we are here? Perhaps a resolution was never possible from our original frame of reference. BSM: The question wasn't well defined. If we had stumbled upon a correct solution among all of our permutations, we wouldn't have had any hope to distinguish it from the faulty ones. Nor did we have a method to reliably test it. FP: We were trying to understand what lies beyond a point of no return, while having yet to pass it. BSM: Only those who have seen the other side can know the answers, but by definition they can never venture back to deliver the knowledge they have gained. FP: Perhaps that is why you need to wake up, little visitor.