Species Names
Dayman: Cruvan Superior
Nightman: Cruvan Retrosepsus
Typically both of them are just shorted to Cruvan. Adjective is Cruvanite. Plural is Cruvans.

Planet: Cruval 2
The planet is nearly tidal locked because of its close orbit to its star. A ring of artificial satellites are in a perpetual geostationary orbit along the planet's twilight zone, which project a hard light barrier towards the planet's surface. As a result, the planet look like a sideways Saturn from a distance.

Day Government
This side of the planet has a singular government which controls all aspects of the planet. There are no private businesses or public opposition towards this government, which employs all members of the Cruval race. The government is divided into five divisions, which is further divided into a labyrinthine bureaucracy with dozens of layers of management. A singular entity called The Solar Unity leads all divisions. The Solar Unity is the head of the five divisions, all put into a machine that allows them to think as a singular organism. The Cruvans that make up The Solar Unity hold their position for life, replaced with the second highest ranked member of each division should they die. The Solar Unity resides in a station that rapidly orbits near the surface of an undisclosed star, having relocated after the previous Solar Unity which orbited Cruval 2 had been killed when a group of rebel Cruvans destroyed their station.
The Ministry of Land is in charge of all architectural work. Because of the slowly moving wall, all buildings on Cruval are made out of hard light (The same sort of technology that Dayman uses). New buildings must constantly be designed and built to replace the destroyed architecture at the Dusk Wall.
The Ministry of Labor is in charge of producing all material goods. This is the largest branch, which has almost 80% of the Cruvan population. Because of their numbers, they are seen as the bottom caste on the planet. They are responsible for creating everything not made out of hard light, from vehicles to food to clothing.
The Ministry of Progress is in charge of all scientific pursuits. Scientific progress on Cruval crawled to near stagnation after the construction of the Orbital Wall, having almost entirely focused on attempting to remove the influence of the brain parasites within every member of their species. Worse yet, even progress on that has been put on hold indefinitely when a group of almost one thousand Cruvans that had survived an experimental treatment which allowed them to survive the removal of the brain parasite went rogue. Members of this group broadcast a manifesto across the planet where they named themselves the Awakened Cruvans and demanded that all untreated Cruvans willingly euthanize themselves. While this was being broadcast a coordinated group of them managed to hijack multiple warships and destroyed the previous Solar Unity, before fleeing the system.
The Ministry of Defense is in charge of warfare. After the construction of the Orbital Wall, this division atrophied to the point where it was being considered for removal. After the attack by the Awakened Cruvans, this branch was almost entirely restructured for the sole purpose of hunting down all of their members. Efforts are still ongoing.
The Ministry of Unity manages the other branches. This branch is the smallest, and their inherently higher positions within the bureaucracy means members of this branch are afforded noticeably more privileges than members of any other branch. After contact from the primary, this branch was expanded to also include  ambassadors and most other off planet members of the species, although these newly added positions don't carry the same clout as their on-planet counterparts.

Night Government-
There's this dude named Keith, and everyone just agrees he's in charge, but since he's so chill he like, never asks anyone to do anything. He's pretty rad like that. Government's for nerds anyways.