Tier-Zero Class Warship

The Tier-Zero Warships are a UNSC classification of an exeedingly rare Exile Warship - an estimated 3 are currently in existence, though none are expected to be in service. The origin of these warships is speculated to be from the retreating Precursor fleet that was not damaged or deteriorate as much as expected. The Warship was seen once in combat in 2638 during First Contact, in the center of a large formation of vessels the vessel was an estimated 7km long and 2km wide.
Warships in this classification are ironically, not of Military Origin, as most Military vessels were likely damaged during the 2,000 year journey from the Black Eye Galaxy, most of the surviving Warships are actually converted Civilian Evacuation craft, constructed directly for the retreat and as such, have survived in moderate shape. The combat capabilities of all Tier-Zero status ships are tales of legend, a single ship, would be able to rapidly destroy an entire Exile fleet - according to civilian folkelore. In reality such ships were clumsy, slow to accelerate, bulky but practically indestructable - its weaponry was only plasma based and was armed with multiple MIRV Explosive Disersal Systems. Its shielding was an incredible feat considering its size and age, it is considered the same as a 26th century Covenant Super Carrier - thanks to its Linear design. The ship's plasma based weapons were far more advanced than the current Exile weaponry, capable of bypassing energy shielding in seconds, though it was not nearly as effecient because of its large energy drain. The main ship-to-ship weapon is still the Fuel Accelerated Missile Attack System or FAMAS Missile, which was basically a fuel propelled anti-matter charge. A point-defense system of Tier Zero class is capable of doing moderate damage to a UNSC Service Warship, though is still considered a threat.
The one surviving Tier Zero vessel of actual warship origin is currently of legend, with only one reliable peice of evidence to its existence; a Tier Zero status vessel was seen leading the conversion of New Kholo of unknown design.
The UNSC maintains the existence of these warships of classified, as the knowledge of pristine condition warships of original Precursor design would cause morale to plummet, these vessels are capable of destroying UNSC Frigates with very few FAMAS strikes and could destroy unknowing battlegroups of small size with a single MIRV Weapon.
The most effective way of disposing of a Tier-Zero class vessel is to temporarilly disable to vessel and deploy boarding craft to destroy it from within, or Multiple MAC Strikes at a single point of the vessel's less-armored underside.
=====Ships of the line=====
*C-001 (Destroyed)
*Pinnacle of Hope
*Salvation
*Guardian of the Mantle