UNKNOWN ISLAND-CITY LANDMASS - URBAN REFUGIA
RESIDENTIAL STRUCTURE UR/RS11863

"Golf-Three-Three, transmit nearby enemy positions to VISR, outlines only."

Spartan Martinez laid prone next to a collapsed window, the tip of his rifle's barrel nestled within the alcove. He gave no outward reaction as one of the superpredator bugs crawled past their structure, laying a trail of webbing behind it. Next to him, PFC Delve tightened his grip on his sidearm.

"SPARTAN-IV-311 and Fireteam Bravo Zebra are Oscar-Mike on AV-14s, ETA thirty-eight minutes," informed Aeona. "Delta-One-One has been fast-tracked into service, antipersonnel ordnance loading in progress, ETA eighteen minutes. Both of our F-41s are still undergoing safety checks and refueling procedures, and unknown functionality present in Hotel-Two-Five-Nine's software will further delay-"

"Received. Continue to track and monitor enemy movement."

The next nine minutes passed by slowly. At one point, Aeona chimed in to inform the two isolated UNSC service personnel that a complete vacuum had spontaneously appeared somewhere in UR/LS3's internal space, and all six unknown bipedal aliens - henceforth designated as UPTs, or Unknown Priority Targets, and numbered appropriately - were trapped within the affected zone. Half a minute later, the vacuum had collapsed and the atmosphere within the zone had returned to normal. Unfortunately, the ONI observation drone had ceased visual transmissions long before the incident, having accidentally blundered into a web while avoiding visual detection by the UPTs, though it was able to pick up air currents generated by the passage of some airborne creature roughly three meters long in apparent pursuit of the aforementioned six contacts.

"Additional purification and sanitation constructs vectoring towards UR/LS3, six in total. Local superpredator species avoiding contact and seeking concealment. Be advised, substantial seismic activity detected with-"

A section of UR/LS3's dome-like shell erupted, sending a blue-and-silver object hurtling past the two hidden UNSC soldiers, whose HUDs shifted to display object identification and track its impact site. The feed from the Pelican hovering above rapidly stabilized on the object, revealing the form of one of the unknown bipeds; a further insert picking up on its vital signs. Low. Consistent with an unconscious individual.

The six purification constructs arrived on scene no less than thirty seconds later, surrounding the biped. For a few seconds, they stared at the being, before one of them reached out with its angular energy weapons and slid them under the blue-and-silver UPT-3. Lifting it up, the construct sprinted for the gaping hole blasted in the side of UR/LS3, with its compatriots scrambling across the ground in swift pursuit.
With one camera focused on the constructs, and a second on the cavity, the Pelican observed the purification robot holding the biomech hesitate at the new entrance before proceeding inside. Its fellow constructs displayed no such delay, streaming in through the same gap once their path was clear. Less than twenty seconds later, movement was detected within the hole before UPT-4 emerged, carrying UPT-3 over its shoulder as it began to make its own descent toward the street.

"Three superpredator insects shifting into pursuit positions, remainder are continuing to wait in place. Seismic activity within UR/LS3 still increasing."

The brown biomech reached ground level, quickly moving to the nearest access hatch that led to the subterranean passageways that spread out beneath the island-city. Just as the pair had vanished below the ground, another section of the massive dome exploded, and what appeared to be a flying biomechanical moray eel coursed through the resulting cavity, gaining altitude and vectoring in the direction of the industrial refugia.
Aeona promptly alerted the inbound AV-14 flight about the airborne creature, and received a flurry of acknowledgement signals in turn. Spartan Martinez watched one of the pursuing bugs grasp the lever on the subterranean access hatch with its mandibles and turned it clockwise, while the other two dug their foreclaws under the lip of the subterranean access hatch and flipped it open - and his eyes slightly widened as the implications became clear.

The creatures understood what those apertures were. They could open doors. And as they slipped beneath the ground to chase down the separated pair of bipeds, making sure to close - and lock - the access hatch behind them...

"Golf-Three-Three. Ground-penetrating radar. Focus on the two unknowns. Stream to HUD."

All three UNSC personnel in the immediate area watched as what was probably the blue one was laid down, shivered, regained consciousness. They watched as the brown one knelt beside them, appeared to converse with them, even as the bugs snuck down the tunnel and closed the distance. They watched as combat was initiated, as the bugs unleashed their energy weapons, knocking down one of the bipeds and surrounding it in an electrical energy field. They watched as the second biped's movements became more and more sluggish until they were immobilized, and then the bugs moved in to secure their prey, dragging them off - still alive - down the tunnels...

"Delta-One-One is now airborne, and will be on station for area clearance in thirty seconds!"

Specialist Chez cursed as the other four UPTs emerged from the cavity torn out of UR/LS3's side, climbed down to the street, and attempted to enter the caves below - only to find the actuator on the nearest hatch would not comply. The bugs on the rooftops and in the alleyways around the bipeds all began to shift, to orient themselves to pounce, to spring the trap they had prepared...

"Delta-One-One, potential collateral downrange. I repeat, potential collateral downrange. Hold off on that ordnance, switch to guns, fire mission danger close, marking targets on your HUD," SPARTAN-IV-311's voice cut in over the comm line. "Aeona, spin up Golf-Three-Three's active countermeasure dispersal systems, we're going to need a distraction in a few seconds. Just enough to divert attention from our movements."

"Copy that, SPARTAN," A1C Amundsen responded. "Delta-One-One, switching to guns and waiting for the cue."

"Martinez," Clarke inquired, "PFC Delve green?"

"No serious injuries, still combat-capable," the Spartan replied as the pair began to crawl towards the entrance of the structure they had taken refuge in.

"Good to hear, Apex Four. Change of plans, though. Aeona says the two unknowns separated from the rest of their group represent a priority-one opportunity to acquire information about our current location. Golf-Three-Three will deploy countermeasures to create a light show, mask your movements while you get to one of the access points to the city's underground. Once you get below, the Pelican will remain on station to guide you to the UPTs via GPR. Aeona! Fire all chaff and flare pods... now!"

ONI Pelicans had access to various esoteric stealth measures. From light-bending active camouflage to heat-dampening panel arrays, their birds were built to be undetectable unless they wished to be seen. Equipped with a respectable amount of chaff pods and flares, the average spook-fit D79 could soft-kill an entire light frigate's weight of munitions with ease.
It was into the atmosphere of a fog-obscured, web-choked urban city street that Golf-33 deployed its entire onboard stockpile of copper-nickel-silver nanolaminate alloy strips, which rained down from the sky as it flew by on its pre-marked route. Simultaneously, a torrent of high-intensity incendiary flares vomited out from apertures in the tail of the Pelican, igniting a mere four seconds after being launched. The captured starlight refracted off of the falling shards of nanolaminate, spreading the illuminative effect far beyond what the flares would be capable of producing on their own. Both camera and radar lock were immediately lost on the bipedal biomechs as the glow enveloped them. The bugs, temprorarily blinded by the sudden change from darkness to blazing radiance, began lashing out in their frantic attempts to escape the incandescent aura.

Most of them wouldn't get the chance. A combination of 110mm and 120mm shells rained down from on high, stabbing into their clustered formation and turning the unfortunates that were directly hit into rapidly expanding clouds of fluid mist and metallic shrapnel. The impacts walked their way up the line of buildings, smashing through bug and roof and wall and floor alike along their destructive path.

Spartan Martinez and PFC Delve, active camouflage engaged, emerged from their shelter and sprinted up the street before sliding to a stop in front of one of the relevant access hatches. Apex Four seized the actuator, cranked it over, and tore the aperture open. The Trooper didn't bother grabbing onto the ladder leading into the abyss, instead snapping to a near-perfect attentive pose and dropping into the darkness like a Marine at their Q4 ODST training, relying on his suit's thruster system to keep himself level. Martinez was quick to follow suit, slamming the hatch closed as he plunged below the street.

-

METRU NUI - LE-METRU
ARCHIVES LEVEL ONE

Onewa regained consciousness with a jolt, his eyes flickering from right to left. He couldn't move, couldn't speak - and the low-intensity electric field surrounding him kept disrupting his concentration every time he called upon the power of his Komau. What he could see, lit only by the rare still-glowing lightstone embedded in the tunnel walls, was the hindquarters of the Visorak spider, immediately reminding him of his current predicament. He began to struggle again, but a sharp pain in his lower legs swiftly rendered him immobilized once more - one of the spiders must have bitten him.

For how long they carried him, he was uncertain. All the Toa of Stone could hear was the constant patter of what must amount to at least three Visorak - which meant that Nokama was still with him. Probably. He didn't want to dwell on the alternatives. He raged against his own body, demanding that he should fight, that he call upon the rock and stone around him and crush the spiders - but it was no use. The Visorak marched on.

And then they stopped. Silence reigned in the tunnel, broken only by the sound of water dripping, the sparse sound of some unknown Rahi roaring somewhere off in the distance, the footsteps approaching from behind - wait.

Footsteps. Heavy ones.

The spiders immediately dropped their cargo. Onewa slammed to the ground with a grunt, while no sound emanated from Nokama. The Stone Toa found his anger rising evenly with his fear - fear that the Visorak had done something irrecoverable to their water-sister. One of the spiders cut away at the cocoon enveloping the Toa Metru of Water, before splaying itself over the webbing - as if it had been dealt a severe blow and lay lifeless, its corpse draped over the body of its prey.

The other two spiders climbed up onto the ceiling of the tunnel, one finding yet another access passage to squeeze into, before spitting webs to obscure the sole illuminating lightstone. And there they waited, appearing so still as to be mistaken for statues.

The footsteps approached. Onewa could tell they were bipedal, and that there were two of them - either that, or whatever came around that corner would be yet another Visorak-mutated monstrosity with out-of-step hind legs. He felt mixed emotions - joy at the impending rescue, terror at what might have happened to the other two members of their team. As the footsteps drew closer, he could feel the impacts transmitted through the stone around him. One set heavy, one set lighter. One a Toa, one... probably not. A Matoran?

The unknown beings turned the corner. Only sixteen bio separated them from the first spider, of which Onewa thought he could see the bare outline of in the near pure-darkness. Fourteen. Twelve. Silence.

A crack of thunder split through the tunnel, a brief flash of illumination flickering alongside, followed by the pained screeching of one of the Visorak. The screech was cut off by a second thunderclap and yellow-orange flash, before the entire tunnel was lit by a crimson glow. A figure charged in next to him, swiftly drawing back in time to avoid the pouncing spider from above. The red glow was temporarily obscured by the bulk of the Visorak as it tilted its abdomen up, unsheathing its launcher - and then it, too, screeched as the fluorescence vanished entirely, only to be replaced with a sapphire incandescence. Whatever was happening to the spider, it was screaming - not a battle cry, but a shriek of sheer agony, further punctuated by a hissing noise, all of which was abruptly cut off in a complete resurgence of both colors and a loud thump as the head of the creature, cleanly severed from the rest of its body, landed on the Stone Toa's chest.

Whatever this being was, it wasn't one of his brothers. None of them would have physically torn apart a Visorak, at least not with the same method as... what he had just partially witnessed. The bipedal individual stalked past the still-immobilized Toa of Stone, towards Nokama, a sapphire-hued energy-coated sword emerging from its left arm. Adrenaline coursed through Onewa's body, and he called upon the power of his Komau, directing all his focus towards the unknown being, demanding it stop... to absolutely no effect. His muffled shouts went unheeded as well as the individual reached the fallen Water Toa and... extinguished its blade?

Onewa could see the afterimage of the being - too tall to be a local Matoran, but too short to be a Toa - as it kneeled next to Nokama. He couldn't see what happened next, but he could hear all Karzahni breaking loose. The spider had leapt up, slamming the unknown warrior against the tunnel wall, and the Visorak had let out a bloodthirsty hunting screech. More thunder filled the tunnel as a series of projectiles began to explode on its carapace, each detonation illuminating the scene reflected in the eyes of the dead Visorak next to him. The second being rushed past the still-restrained Stone Toa, only to fly against the tunnel wall a second later, impacting with a loud BANG and a pained yowl.

The sound of metal grinding on metal drew the Toa's attention back to the pinned warrior. The Visorak had forced its terrible jaws against the being's mask, and was tearing away at its surface, with enough sparks flying to readily illuminate the scene. Evidentally, the being had lost its probable grips on the spider's mandibles, and the venomous Rahi was about to claim its prey. And then the Visorak's head simply exploded.
Onewa blinked. The spider dropped limply to the ground, its head brutally caved inwards from below. The warrior was gasping, its breath echoing in the tunnel, as it turned its head to face its companion, who was struggling back to its feet to evidentally assist in pulling the now confirmably-dead spider off.

The warrior with the damaged Kanohi grunted something as it stood up, shaking its left arm, before illuminating the tunnel once more with the sapphire blade. The grunting noises continued. The smaller warrior turned to tear off the web obscuring the lightstone, before it gazed down at the still-restrained Toa of Stone with its inflexible visage. Whatever Kanohi this being wore, he had never seen one like it before. A set of vibrations in the ground beneath drew his attention away from the near-faceless entity, and with some concentration, he could feel the impacts of four pairs of feet; a striding pattern he was considerably more familiar with.

Nokama came back to consciousness with a jolt, emitting a short, pained shriek that immediately had Onewa struggling to move once more, all the while reaching desperately out to the local rock that held up the tunnel to slide underneath him, its coarse surface quickly shredding through the webbing. Sitting up, the Stone Toa's gaze immediately fixed on Damaged-Mask, who was kneeling over Nokama, its weapon-hand on her head, glowing with orange energy. Damaged-Arm had since shifted to their partner's side, pulling at Nokama's own Kanohi, seemingly attempting to take it off.

With no further hesitation, Onewa let the two columns of stone that he had built up next to the two warriors freely extend, slamming into the beings and launching them further down the tunnel, before collapsing the tunnel to form a barricade between them and the two rogues.

-

METRU NUI - PO-METRU
CHUTE STATION #309

Sarna breathed evenly, controlling her fear, as the whirring noise drew closer to her hiding place. She had taken cover in the former transport hub connecting Po-Metru with Onu-Metru, both avoiding Visorak patrols and evading her apparent pursuers along the way. The small avian Rahi that was supposed to be waiting for her return was dead - she had seen the dessicated remains half-trapped in a web near the entrance, and barely avoided being caught herself by the resting Oohnorak that had likely devoured the bird.

What had followed was a Muaka-and-Gafna exercise, culminating in successfully luring the spider into conflict with the four-strong group of false-Rama that had so-far endured their pursuit of her this far into Visorak-controlled territory. Only two had survived the resulting conflict, and one had been so critically damaged that it had simply shut down and fell apart not a minute afterward.

Now, she was trapped at a dead-end hallway, her forward path blocked by a collapsed ceiling, as the final false-Rama hovered around the corner, holding position. It was hesitant to turn the corner - why would it risk being destroyed and it's prey escaping, after all? A minute later, it had began to grunt at her. High-pitched gutteral noises, organized into a pattern that started to repeat every other minute. Communication? Possibly, but there was no way for her to understand what it was saying. Perhaps if she was a Toa, and had a Rau... but as a Matoran, the only form of effective communication she could utilize was the kinetic kind, delivered via her Kanoka launcher.

And so they remained locked in a stalemate, the false-Rama continuing its series of primal noises, while Sarna held her Kanoka launcher steady and fixed on the corner, a level 3 freeze disk primed and ready to fire...