Prologue
Reach, Epsilon Eridani system
11th June 2559
Glowing missiles arc through space, leaving a vapor trail. Many of them are intercepted by other missiles and point defense guns, but some get through. Five of them smash into a Vindication – class light battleship. Upon impact, they generate slipspace ruptures. The ruptures ate into the body of the battleship, bypassing the shields. Lights of the struck vessel flickered and died out. A Strident – class frigate meets the same fate, except it is split into two. Several Covenant ships also take hits from the missiles and get crippled by the slipspace distortions generate.
The fleet of UNSC ships return fire, opening up with MAC guns and missiles bays. The former lobbed 600 ton depleted uranium shells coated with ferric-tungsten at 30 kilometers per second. The latter spewed out missiles at insane rates. Orbital Defense Platforms attack, firing 3000 ton shells at 12 000 kilometres per second.
Covenant warships, a mix of CCS-class battlecruisers, CPV-destroyers, various smaller vessels and a single ORS-heavy cruiser, join the battle. Beams of brilliant white light shoot from the capital ships as they fire their energy projectors. Slower plasma torpedoes, essentially bolts of magnetically contained superheated gas, follow through.
The munitions travel through space and hit their targets, which appeared to be two Charon-class light frigates and a Halcyon-class light cruiser. Explosions of human and Covenant weapons completely engulf the warships. But the ships only resembled the old UNSC warships, because formerly invisible energy barriers flared up as the blast dissipated.
"Enemy is intact!" shouted the officer of a UNSC Autumn-class cruiser.
"To withstand combined UNSC and Covenant attack," the captain muttered, "what the hell are we facing?"
He looks at the holographic displays of the ships. Although they resembled the old UNSC warships, they had insanely powerful energy shields. Not even Covenant energy projectors, which have ripped apart human heavy cruisers, did much. Visually, they also possessed swirling strips of glowing lights on their surface.
A slipspace rupture appeared in front of the ships. From it, a massive construct formed of many levitating polygonal pieces appeared. It vaguely took the shape of a bird and is easily the size of a Covenant destroyer.
"It's a Guardian!" a San'Shyuum shipmaster exclaimed.
"Cavalry has arrived," a human captain said, "surely Forerunner technology can halt the advance of these demon ships."
"Don't worry," said a female voice, "I've got your back."
"Cortana?" asked the captain.
A blue aura gathered between the wings of the Guardian as it charged up its energy. A massive EMP burst propagated through space, washing over the unknown ships.
"NOW!" an admiral ordered, "FIRE!"
Several ODPs fire their super-MACs again, concentrating on the cruiser. Every slug delivered the energy equivalent to 51.6 gigatons of TNT. Even Covenant capital ships crumbled under the super-MACs. Explosions obscure the ships, but when they died out, the Halcyon – class cruiser remained intact.
"What?" the voice of Cortana said, "Immune to EMPS?"
The new ships return fire, attacking with blood red beams of energy and more missiles. The energy beams slice through shielding and metal, shredding defensive lines of Reach while the missiles rip material from the ships. In mere minutes, UNSC, Covenant and Forerunner ships alike crumbled under the assault.
Soon after Cortana gathered control of the Guardians, a mysterious new fleet of ships appeared. Although taking the forms of old model UNSC ships, they packed technology superior to anything the Covenant or UNSC had in their possession. ONI personnel claimed that their power surpassed that of the Forerunners themselves. The ships prowled through the galaxy, decimating everything the Covenant and UNSC could throw at them. For unknown reasons, they avoided attacking planetary targets, concentrating on space based entities.
Humans and Covenant alike are trapped on their planets, forced to mothball their ships until a method of destroying the new ships could be discovered. Travel between planets was cut off, except by Covenant stealth ships which could enter slipspace from within a planet's atmosphere and remain hidden. Communication was facilitated by Cortana, using the remnants of the Domain. The UNSC, Insurrectionists and various Covenant factions entered an unspoken alliance to deal with the new threat.
The new ships were called the Fleet of Fog, as they radiated a fog like residue upon entering normal space from slipspace. And like fog, they can be seen, but not destroyed.
Well guys, that was the first chapter of a cross over between Halo and Arpeggio of Blue Steel. Hope you enjoyed it.