Osa-class Corvette

Entered service: 2431

Missile corvette operated by the CMA in the 2400s. A little over 2 dozen remained in operation by 2525. At least one was captured by Insurrectionists, the rest were obliterated by the Covenant.

Armament: 5 20mm CIWS guns, 4 M23 Ares missile pods

Length: 221 meters

Akita-class Corvette

Entered service: 2435

Heavy corvette operated by the CMA in the 2400s. Like the Osa there were around 2 dozen left in service by 2525, all of which were destroyed by the Covenant

Armament: 4 20mm CIWS guns, 2 65mm autocannon turrets, 4 M30 Howler missile pods, 3 M23 Ares missile pods

Length: 265 meters

Superb-class Frigate

Entered service: 2488

The Predecessor to the Charon-class frigate, the Superb-class can be divided roughly in two halves: the "Block-1" Missile Frigates and "Block-2" Light Frigates armed with a MAC and introduced as the Insurrection started to get worse. The latter group was hastily replaced by the Charons. Many ships in the former group were sold off to private defense fleets and occasionally refitted with MAC guns, the rest were unceremoniously handed over to the CMA after the UNSC subsumed the organization in the early 2500s. A few of both variants were captured by Insurrectionists, with the Bellerophon being the most notorious example.

Armament: 8 M50 Archer missile pods, 4 M300 Streak missile pods, 5 M670 Bulwark 20mm CIWS guns, OR 10 M50 Archer missile pods, 6 M710 Bulwark 20mm CIWS guns, 1 Mark I 80BR5R1 MAC gun

Length: 478 meters

Zodiac-class Light Destroyer

Entered service: 2450

Intended as a low-cost screening ship at a time when vessels like the Diligence and Resolute-class were considered cruisers, the Zodiac-class was produced en masse for the UNSC and CMA as an agile, missile-spewing menace to both attack fighters and starships. By the time of the Insurrection it was regarded as a brittle deathtrap often plagued by maintenance issues, particularly due to the mediocre performance of 3 such ships during the Callisto incident. Unlike even older ships such as the Diligence class, the Zodiac-class was never refitted with a MAC due to its small size.

Obsolete though the class was, it was still of limited use as a convoy escort or a ground support ship during the Insurrection, which is why several dozen were still in service when the Covenant attacked. Like the Osa and Akita-class Corvettes, many Zodiacs were destroyed in the opening years of the Covenant war, caught in unexpected alien attacks or unwisely thrown into action as stopgap measures to augment shredded battlegroups. Their all-missile armament proved ineffective against Covenant shields in all but the most fortuitous and well-planned volleys. The surviving ships were often sent to bolster defense fleets in systems thought to be a "safe distance" from Covenant attack routes, where their presence might serve to calm the nerves of locals who didn't know any better.

Armament: 7 Ares missile pods, 4 M600 Helix 20mm CIWS guns.

Length: 364 meters

Resolute-class Light Destroyer (h/t Sins of the Prophets 2)

Entered service: 2456

Reclassified as a Light Destroyer after MAC guns became the norm, the Resolute-class was once considered a cruiser in terms of size and role. This class was in many ways similar to the CMA's Diligence-class, albeit honed by another 25 years of advancements. By the 2500s, the remaining Resolutes were upgraded with titanium-A plating and twin "outrigger" MAC guns, though the latter only made them slightly more lethal than a Charon-class frigate, resulting in their downgrade to Light Destroyer classification.

Armaments, 2525: 2 45C5R2 MAC guns, 6 M60 Sentry turrets, 1 M33 Spitfire turret, 6 Archer missiles pods, 8 M800 Rampart point-defense guns

Length: 560 meters

Champion-class destroyer (h/t AugustStorm1945)

Entered service: 2486

A CMA missile destroyer with extra cargo space designed as a long-ranged patrol ship, a flotilla leader for Zodiac-class destroyers or frigates, and to support MAC-armed cruisers like the Victoria-class and the planned Vulcan-class. Heavily modified both before and during the war, usually by replacing its cargo and troop bays with a MAC gun.

Armament: 24 M40 Ares missile silos, 4 Howler missile pods, 4 M800 Rampart guns, 6 M710 Bulwark guns, OR 1 7C4R8 MAC gun, 3 M66 Sentry autocannons, 18 M58 Archer missiles pods, 6 M870 Rampart point-defense guns

Length: 552 meters

Chimera-class Destroyer (name is from Sev40)

Entered service: 2497

The first UNSC Destroyer class designed from the ground up to mount a MAC gun, the lessons learned from the Chimera-class would be used to develop the iconic Halberd-class destroyer. Following the introduction of the Halberd-class, most Chimeras were given to the defanged CMA as hand-me-downs like many other obsolescent UNSC ships. They served adequately against the Covenant, but were ultimately reduced to nothing more than a memory by the late 2530s.

Armament: 1 7B3R4 MAC, 16 M58 Archer missile pods, 2 M66 Sentry autocannons, 5 M800 Rampart Point-defense guns

Length: 530 meters

Paladin-class Destroyer

Entered service: 2528

As the Halberd-class supplanted all other destroyer types, it was only natural that some in the UNSC Navy would look at this runaway success and ask the question: "what if we made it bigger?" Several projects were given the greenlight to explore this concept in the late 2510s, but all were put on hold due to cost concerns. Additionally, the Halberd-class had already proven more than adequate in facing whatever threats the Insurrection could bring to bear.

With the arrival of the Covenant, the idea of a "Heavy Halberd" was hastily revived, resulting in the creation of the Paladin-class. Ultimately, the number of Paladins produced never reached the triple-digits, as the course of the war drove the Navy both to continue producing the less expensive Halberd and to develop even more extravagant designs. Very few survived the war.

Armament: 1 18B8R4 dual MAC battery, 32 Archer missiles pods, 8 M870 Rampart guns, 4 nuclear missiles.

Length: 589 meters

Trident-class heavy destroyer (h/t Auguststorm1945)

Entered service: 2547

An experimental destroyer design equipped with a rapid fire 160cm MAC, the Trident-class made a name for itself at worlds like Sigma Octanus IV, Reach, and Earth, where the last of its limited production run was destroyed. The design lives on in the Navy's post-war Cole-class destroyers.

Armament: 1 2Y30R19 MAC gun, 36 M58 Archer missile pods, 10 M870 Rampart guns, 4 M55 Castor turrets, 6 Nuclear missile silos.

Length: 651 meters

Expeditious-class Cruiser (h/t Auguststorm1945)

Entered service: 2474

The Expeditious-class was meant as an experimental class intended to test the viability of cruiser-sized ships armed with MAC guns. Generally regarded as both under-gunned for its size and lacking in transportation capacity, the class was superseded by the Tenacious-class less than 10 years later. A few were repurposed as training cruisers.

Armament (training cruiser configuration): 1 3Y12R1 MAC, 2 M30 spitfire turrets, 4 11A2R1 coilgun batteries, 4 M60 Sentry turrets, 18 M42 Archer missile pods, 4 M96 Howler missile pods, 12 M300 Streak anti-fighter missile pods, 4 M710 Bulwark point-defense guns, 6 M800 Rampart guns, 4 M810 Helix CIWS guns

Length: 1203

Tenacious-class Heavy Cruiser (h/t Auguststorm1945 and Dirgeofcerberus111)

Entered service: 2482

The Tenacious class was designed as a successor to the groundbreaking Expeditious-class cruisers, which was the first cruiser-sized starship to be armed with a MAC. It would be both smaller than its predecessor and armed with a larger gun

The Halcyon-class was intended to replace the Tenacious until the disappointing nature of the newer design became apparent. As a result, Tenacious-class cruisers were given various refits to extend their service lifespans until the Covenant war began. The cruisers were frequently used as stand-ins for the newer Marathons during the first decade of the war, as despite their obsolescence they still hit harder than the Halcyons. None survived past 2539.

Armament: 1 5Y09R1 Heavy MAC, 48 M58 Archer missiles pods, 4 M40 Oxybeles Coilgun turrets, 6 M810 Helix CIWS turrets, 8 M800 Rampart point-defense guns.

Length: 1030 meters

Vulcan Class Heavy Cruiser (h/t Sev40 and Dirgeofcerberus111)

Entered service: 2493

Designed by the CMA Navy in the early 2490s with the sole purpose of outdoing the Tenacious-class, the Vulcan-class had practically twice the firepower of its UNSC counterpart, literally in the case of its twin MAC guns. Supporting this unparalleled primary battery were several coilguns, dozens of missile pods, and several fusion rockets. As the common joke in the 2510s went: "The Vulcans made the Halcyons obsolete".

The tradeoffs for all this weaponry became painfully apparent when the Covenant started advancing on human space. Plasma beams proved devastating to the Vulcan-class because they could rapidly cut across hulls that were usually festooned with weapons, triggering dangerous chain-reactions. In an ironic twist of fate, the Tenacious-class cruisers the Vulcan had been designed to upstage went on to outlast their rivals in battle against the Covenant, but only by a few years.

Armament: 1 9L18M2 MAC battery, 130 M48 Ares missile silos, 20 M300 Streak anti-fighter missile pods, 4 Crossbow fusion rocket silos, 6 M20 Krait intermediary coilgun turrets, 6 11A2R1 Coilgun batteries, 8 M965 Fortress 70mm point-defense guns, 10 M710 Bulwark Point-defense guns, 6 M800 Rampart point-defense guns

Length: 1218 meters

Constellation-class "Battlecruiser" (h/t Falkeno)

Entered service: 2494

The high-water mark of the CMA Navy, the Constellation-class was designed at the same time as the Valiant-class, though not as a direct competitor. Rather, the Constellation class was envisioned as a sleek, no-frills hunter where the Valiant-class was a bulky "super-cruiser" with extensive CIC facilities. Since they were also meant to serve as an escort for the CMA's supercarriers, no such expensive amenities were needed. The class would be well-armed, yet not as fixated on firepower as the earlier Vulcan-class cruisers were.

In the end, only a few were completed before the full internal corrosion of the CMA was exposed in 2497. The remaining hulls would be seized by the UNSC during their extensive purge and absorption of the CMA, left to collect space dust in shipyards throughout the Inner Colonies. There they would remain until 2525, when the Navy quietly approved their completion in the face of the looming Covenant threat. The time needed to finally bring these malformed ships to life varied depending on how complete they were, as various lessons learned fighting the Covenant were incorporated wherever possible. In the meantime, the few active Constellations were lost in the opening decade of the war.

Armament: 1 50GE1A5 MAC battery, 4 M30 Spitfire turrets, 6 M60 Sentry turrets, 170 Ares missile silos, 24 M300 streak missile pods, 18 M710 Bulwark Point-defense guns,

Length: 1598 meters

Artemis-class Battlecruiser (h/t Falkeno and Sins of the Prophets)

Entered service: 2537

The Artemis-class was designed to engage Covenant ships at long-range with its two super-heavy MAC guns. Several ships in this class were lost in the Navy's unsuccessful attempts to hunt down and corner the Fleet of particular justice.

Vanguard-class Battleship (h/t Falkeno)

Entered service: 2492

Designed to counter the Punic-class supercarriers being constructed by the CMA, the Vanguard was a "carrier-slayer" built purely for ship-to-ship combat, a sharp contrast to the more multifarious design philosophies of other UNSC ships that usually made concessions for ground complements of various sizes. When the CMA ultimately gave up without a fight in the late 2490s, the class was gradually phased out and put in reserve, as cruisers and assault carriers became the preferred ships of last resort for dealing with the hit-and-run strategies of various Insurrection groups where larger ships would simply waste fuel.

Reactivated in 2525 after the discovery of Harvest's fate, the Vanguard class wouldn't be ready for battle until 2528. But when they did take to the field, the Covenant paid attention. As fate would have it, the Vanguards would even outlast their intended successors by surviving the war…

Tunguska-class Battleship (h/t Sev40 and Sins of the Prophets)

Entered service: 2496

The Tunguska-class was the UNSC's answer to the Covenant CAS-class carriers and other massive Covenant capital ships. Though first laid down in the early 2540s, their construction would be constantly delayed due to the deteriorating war situation as shipyards attempted to compensate for unsustainable loss rates among smaller ships with increasingly limited supplies of war material. Only after Admiral Cole's victory at Psi Serpentis bought humanity some much-needed breathing room did construction of the massive ships finally resume at an accelerated pace. By the time the first ship was completed in 2546, the Covenant were well on track to recovering from the disruptions inflicted on them by the battle of Psi Serpentis, Operation Grey Veil, Operation Hemorrhage, and Operation Torpedo. This meant that Tunguska and her few sisters would see action practically non-stop for the next few years and be worn down accordingly. None survived the war, but the class lives on in a highly-altered post-war variant, only two of which have been commissioned as of 2577.

Phoenix-class colony ship

Entered service: varies

A few surviving Phoenix-class ships were rebuilt during the war for various stopgap roles, the Spirit of Fire being the most iconic but not the most extensively redesigned of the bunch.

Noryang class Light Carrier (h/t TheAussie1417 and Sins of the Prophets)

Entered service: 2461

A CMA design that would be retroactively reclassified as a "light" carrier by the 2500s. Several dozen Noryangs were built, though most were put in reserve following the UNSC's dismantling of the CMA. They were hastily reactivated as part of the UNSC's large-scale mobilization in November 2525 and were ready for action by mid-2526. By 2536, less than a half-dozen remained active.

Belisarius-class Heavy Carrier (h/t Auguststorm1945)

Entered service: 2532

Another wartime class inspired by fanciful Insurrection-era designs that eschewed planetside support in favor of full-on space warfare. The Belisarius-class could carry just under 100 fighters and was armed with a twin MAC.

Armament: 20C5R9 MAC battery, 18 M66 Sentry Autocannons, 80 M58 Archer missile pods, 24 M390 Streaker missile pods, 20 M910 Rampart turrets, 28 M965 Fortress point-defense turrets, 20 M810 Helix CIWS guns,

Length: 2980 meters

Eion-class Light Carrier (h/t TheAussie1417)

Entered service: 2535

A response to the harsh realities of the Covenant war, the Eion-class was put into production shortly after the larger Belisarius-class, though the two were produced in equally limited numbers due to increasingly limited shipyard capacity.

A/N: I've decided to post the definitive (for now) list of all fanon war-era UNSC ships in the setting. Almost all credit goes to Sins of the Prophets, the Halo fanon wiki, and Daybreak for creating these designs. If it's not on the list, it's most likely canon anyway. If it's canon and on the list (Osa, Akita, and Zodiac AKA "light destroyer") then I'm just outlining their weaponry. If the weapons aren't there, it's because it's the same as the Halo fanon wiki specifications. I can't tell you whether any of these will appear in the PRESENT half of the story, I'm just pinning this all down to clear up the war side. I am in large part inspired by AugustStorm1945 and his effort to make the UNSC navy feel more like an actual Navy instead of just having the same half-dozen ship classes across the whole war.

Next chapter coming in 30 minutes (if I don't pass out)

For reviewers:

WhatdidIdotogethere: Possible preview, possible reference to ships named in canon just for jun