The Heart of Unity is a Dyson Sphere of Iconian construction like no other. Known historically through regional mythology as the 'Heart of War', this rumored sphere was supposedly an Iconian superweapon built towards the end of their tenure as custodians of the galaxy as a last ditch desperate attempt to end the Horde threat. The name was altered after the newly formed Galactic Coalition defeated the Horde in 2422 and began to resettle the 'Heart' as it was often referred to locally.
Unwittingly rediscovered by the crew of the Valley Forge when they established a connection to one the Heart's gateways during an excavation of an archaeological site on the planet Newfrika, it went on to become the catalyst for their famous exodus towards the far galactic rim of the Alpha Quadrant. The significance of this particular facility only became apparent much later in this historic mission, as the crew learned of it's true nature.
Whilst there was some semblance of reality in the Heart's associated mythology, it had become predictably skewed over time. The Heart was a superstructure dwarfing even the Solanae sphere, comparable in overall proportion to the Sol System. It's immense scale gives it a deceptive appearance of being truly spherical, when in fact it is an ellipsoid. This was a unique feature to the Heart over other Iconian installations, and considered pertinent to it's true function. Unlike other spheres, this one was not constructed solely by the Iconians, but in collaboration with the Nuhar - architects of the starship-sized colossal AI's who still roam the rimward regions in the 25th century.
With both galactic superpowers facing the reality of their demise at the hands of the Horde, they built the Heart primarily as an ark. This ark was populated with records of the entire Iconian Empire, and their complete galactic genetic library to preserve species made extinct by the Horde for later rebirthing. This was the reason for the colossal scale and unique layout; surrounding a BSG (Blue SuperGiant) star, the ellipsoid shape allowed preservation biomes to be constructed to fully replicate different planetary conditions as required. When the uprisings brought about the untimely end of the Iconian Empire the gateway system was shut down, and the Heart became isolated before completion. The few remaining Iconian scientists added their own genetic records to the Heart's archive in the hopes of one day joining those who are reborn when a greater power finds a means to defeating the Horde.
The mythology of the Heart being a weapon - responsible for it's historical name as the Heart of War - was derived from it's secondary function, which was a means to defeat this galactic threat. The Heart was effectively lost to the galaxy by the gateway shutdown before this could be finalized however, and so remained dormant waiting for a future galactic power to complete it. This function came in the form of psionic amplification which utilized subspace frequencies to spread it's impact across the entirety of the Milky Way galaxy, and was predicted to directly undermine the psionic control element that was driving the Horde forces. This weapon was fired once following a historic conflict between Coalition forces and the Horde army. An Ocampan Starfleet officer was reported to have interfaced with the weapon controls shortly before the Horde forces disappeared from the galaxy.
Further speculation about the psionic impact of this facility came about as a result of the Milky Way's galactic barrier dropping in what seemed to be direct correlation to the incident. Unconfirmed speculation suggests that the Q Continuum created the barrier in order to contain the Horde and prevent it from contaminating the rest of the universe, and that they did so by siphoning the psionic potential of all of the Progenitor's 'children' species seeded across the galaxy. Given the connection now known to exist between the Progenitor's galactic seeding and the Horde itself, this is generally accepted as the most plausible explanation to date.
Following the Horde's defeat, the Galactic Coalition (though not exclusively so; consisting largely of Alpha Alliance¹, Iconian, Colonial², Regulator, Nuhar and Trinity Alliance) unanimously agreed that the Heart would be forever more recognized as the Heart of Unity and a symbol of galactic collaboration and coexistence.
(¹ Alpha Alliance is a generalized term used to define the primary powers of the Alpha Quadrant when represented as one; Federation, Klingon Empire, Romulan Republic/Empire)
(² Colonial is a collective reference to the Arshai and Orion representation as collective core members of the Coalition)
Whilst the first Iconian rebirths were joining the galaxy and the evolution of their survivors had attended the Heart also, they lacked the combined numbers to fully control the facility at peak operations. Because of this, the Coalition agreed that the Iconians would remain overall custodians, but operational oversight would be maintained by the Coalition itself. The central command biome was divided up into a series of provinces which would go on to serve as individualized operational bases for each of the primary members, while secondary and tertiary members occupied states within a parent province.
The central command biome was an atoll with the main command tower sited on the central island, directly overlooking the primary gate. This is also the only direct access to the site of the weapon control system which was decommissioned following the Horde's defeat, which is connected via portal to the otherwise highly isolated facility at the core of the Heart.
Much of the biome has been used for the temporary accommodation of refugees from the Horde advance awaiting resettlement to reclaimed or newly settled worlds. However the Iconian, Nuhar and Regulator Provinces are strictly controlled with no general public accessibility.
Largely controlled by Starfleet - as the only of the three powers with the resources to front an operation on this scale at the time of the resettlement - this region is one of the more rapidly developing of the biome. Starfleet's DSEC (Deep Space Exploratory Corps.) quickly established a base of operations and relocated the bulk of it's fleet here to support the reclamation of former Horde territory. This influx of Starfleet vessels and personnel quickly brought about the opening of an academy annex (ST:UNI).
Whilst the Regulators are not outright secretive, their chosen role is clearly defined and as such they maintain a modest region to provide the essentials to their own operation and do not host any residential districts.
Some states have been isolated to provide sufficient overspill accommodation for refugees. However given the Nuhar's limitations to directly support biological life, this is not yet in use. The 4 Foundries make up the core of the Province and - as the only Nuhar Foundries known to exist with the capability of creating new Constructs - remain closely guarded as the Nuhar's only remaining means of survival. This Province has also rapidly grown into a more generalized shipyard region, with one of the Foundries being used to support the Coalition's first major undertaking in a new fleet of starships.
The Trinity Alliance (Chlasi, Gaton and Erudis) - as one of the more well established unified powers of the rimward region - operates the largest resettlement region within the biome. The psionic awakening has also driven increased activity towards the Chlasi temple which quickly became recognized as a galactic authority on the proper control of psionic abilities.
Whilst recognized as territory of the evolved Iconians, they choose to remain in isolation from the galaxy. As such, this Province is occupied solely by the reborn Iconians and their Heralds. Little is known beyond the existence of the genetic archive and reconstruction facility.
Since the Colonial Arshai & Orions of Vue-En had already supported the refugees during the conflict, their transition of this operation to the Heart was even more expedient than Starfleet's operation. Influence of the increasingly popular High Orion aesthetic revival have quickly established this Province as a centre for all forms of entertainment.
Other biomes are slowly being explored by Coalition scientists, but the vast majority of fleets stationed at the Heart are either securing former Horde territory in the rim, or preparing colonization expeditions to follow.