The Chaos

A creature briefly mentioned by Lyren Killian to be an 'entity' he mentioned that it was an old being that doesn't really have wants or needs and instead simply turns it's eye to worlds and corrupts individuals within.
A creature touched by the chaos is obsessed with the question 'Why does the sun shun the dark?' it drives them mad until they can't tell reality from the question and the dream... typically this takes 4 days-3 weeks.
If an individual fights this chaotic madness then they are visited by the avatars of the chaos, three identical people that 'share you eyes' called Selma, Selene and Arty. They are there to push the madness further and encourage more and more chaos from you until you become an avatar devoted to the chaos.
In terms of the question, it is a curse and a prayer, it cannot be answered and trying to do so is simply a waste of time.
The party have since learned there are several philosophies around the entities and that, more often than not they aren't inclined towards a morality but, rather, they are part of the natural world... in the same way you wouldn't assume water to be evil because it is capable of drowning.
KNOWN INDIVIDUALS AFFECTED BY THE CHAOS:

• Layla: The Helmed Crown and Denizen general was a kind and benevolent follower of Correllon as well as captain of the guard for Oar's Rest. In her dreams she was visited by the chaos and driven mad by it. She was visited by the Siblings of Chaos a week later and driven to further madness. Layla notably visited King's Bay to be helped though chose friends at the MAGUS and not Ardeth's therapy... believing her dreams to be an arcane possession. She did mention an individual in the MAGUS centre (A Genasi named either Ruben or Ruby) who was researching something and seemed deeply afraid of what Layla was experiencing... they asked Layla to return for them to discuss their research with her but she declined. By the time the party met her she was sewing chaos in Oar's Rest by working with the Denizens to destroy Oar's Rest through the elder brain known as 'Dream'.
• The Siblings of Chaos: The party know almost nothing of these individuals away from Killian's knowledge and Layla's statements. They have so far learned they are 3 and that they firmly work for the chaos. The 3 avatars messed up Layla's mind thoroughly to the point where they used trigger-words to make her become more and more insane. Eventually, Layla killed Selma... she then described how they simply laughed together during the murder. After that point Layla's entire morality seemed to flip and she became devoted to the downfall of everything around her. When the party finally met the siblings they were outclassed and almost all killed... In the end Baralas was the one casualty as Kodo managed to defeat Selma but Arty killed Baralas with a fireball. The chaos siblings have a strange and uncanny near artificial appearance and, notably, have twisted and mutated Archania Weave to become one of their number after Selma was killed.
• Inquisitor Dairon:  Dairon was deeply marked by the distorted silhouette and the party pulled her out of it, she was catatonic and deeply sobbing afterwards and was clearly affected. She left the party in Oar's Rest with Olympia promising she will experience the dreams soon and that if she needs the party she should find them.
• Olympia: The bard stepped inside the distorted silhouette in Layla's home and felt as though she was performing in silence beneath a spotlight. She found herself in the endless space with her own eyes watching her and whispering the question. Olympia has been slow to be affected by the Chaos it seems, her endurance and sleep have not changed though she is plagued constantly by the question that she now knows is a curse... though it is strange just how resistant Olympia has been... Olympia learned that she had become the key of the chaos, it's 'representative' in the material plane; however, she lost that status after chanigng her race in an alchemical experiment and has since been free of the chaos.
• Fen: Fen became the key of the chaos after Olympia was freed from it, being asked the maddening question and seemingly showing no symptoms of being hit by it...
• Archania Weave: Archania was struck by the chaos after falling into it's oceans during the party's ocean excursions. She was never retrieved and it was later learned that the chaos swallowed her and dragged her to a demiplane where it has driven her mad, twisted her features and forced into a deadly jealousy of Olympia and Fen due to their status as keys of the Chaos.