Chapter Text
INTRODUCTION (Please read)
Before diving into the fic, let me explain a bit.
While this fic takes inspiration from the Sentinel-Guide universe, I’ve reworked most of its elements to fit my own lore. It can be considered an alternate version built specifically for this story, with bonding/mating being the only concept retained from the original idea.
Below is the custom worldbuilding (This section explains the setting to help readers who are unfamiliar with the genre to understand):
In this story, “Angels” and “Guardians” are government-assigned codenames for Sentinels and Guides. Both terms will be used interchangeably throughout the fic.
— Sentinels (Angels):
Warriors endowed with heightened five senses and extraordinary physical prowess. Their acute senses make them hypersensitive to even the slightest stimuli, leaving them vulnerable to emotional and sensory Overload. When overwhelmed, Sentinels become volatile, their emotions spiraling out of control.
To cope with Overload, Sentinels require the soothing presence of a Guide. Without timely Healing, prolonged Overload can drive a Sentinel into madness, leading them to wreak havoc until they collapse from exhaustion and perish.— Guides (Guardians):
Protectors gifted with the ability to stabilize a Sentinel. Their mental resilience, however, comes at a cost—absorbing too many negative emotions during Healing can leave Guides traumatized or, in extreme cases, drain their Psyche Energy to the point of death. A rare few Guides possess exceptional abilities to sense and manipulate the emotions and moods of others.
Unlike Sentinels, Guides lack physical agility and strength, relegating them to support roles behind the front lines.A single Guide can Heal multiple Sentinels, the same to a Sentinal can be healed by different Guides, but the effectiveness and method depend on their compatibility.
— Healing:
Guides can Heal Sentinels in two ways:
• Spirit Bond: By entering the Sentinel’s mind, a Guide absorbs their negative emotions to provide relief. This is the most common method, used for unpaired Sentinels and Guides, but its effect is average.
• Flesh Bond: Exclusive to bonded pairs. Physical contact—ranging from touch, caresses, kisses, to intimacy—yields the highest efficacy. This method not only soothes the Sentinel but also recharges the Guide’s Psyche Energy. However, it can backfire if performed with anyone other than a bonded mate.
Additional terms, names, and concepts will be explained as the story progresses.
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ARC I: SUNLIGHT RETURNS TO THE EARTH
- No matter how fragile the ray of sunlight, it is still a ray of light -
Earth in the year 10207 no longer has concepts like nations, cities, or continents, because everything has been destroyed beyond repair. The recent Demonic Beasts War has wiped out the entire civilization that once existed, nearly exterminating humanity, turning an Earth once covered in two shades of green into a world drowned in sand and dust. In other words, the world has just gone through an apocalypse.
But then amid the dark night sky, humanity rises once more to reach toward the light. Individuals gather into groups, those groups form communities, the communities build a society, and in that way a new civilization is born. Nestled in the midst of a decaying planet, the survivors who found one another have come together to establish the Safe Zone, not a nation, but a hope for humanity, a place that has sworn to save everyone, leaving no one behind.
Earth is thus divided into three main regions: Safe Zone, Wildlands, The Unknown Land.
The Safe Zone, a society where ordinary humans coexist with those superior individuals: Sentinels and Guides, or as the government calls them, Angels and Guardians. They are warriors and protectors with extraordinary abilities, trained under a special organization, all for the purpose of safeguarding humanity, ready for any annihilation that might happen again.
The Safe Zone is ruled by a government system, but it is actually just a puppet of the Nexus Council. The Nexus Council was founded by the first people who rose up to rebuild society, and from that came a core organization that trains those Angels and Guardians, known as the Golden Blood organization.
The Wildlands, a place where the light of the Safe Zone cannot reach, is a grim and rotting painting, a land not meant for human habitation. The Wildlands were once fertile forests, windy plains, dazzling urban centers lit by colorful lights. But after the war that just ended, everything collapsed, everything was ravaged severely, and just like that it became a gigantic ruin. Cracked roads, weeds pushing through layers of asphalt, and somewhere the low growls of Demonic Beasts, the heavy breaths of Fallen Angels, they echo together in the darkness like a chilling melody.
_
Wildlands, ruins of an old urban center.
Fine dust floats in the air, coating the remains of a city that once blazed with lights. The high-rise buildings now stand as empty concrete skeletons, broken and slumped under the weight of time, the aftermath of that war having turned Earth into a pile of rubble.
Yuta stands on a rocky outcrop, his sharp eyes watching a squad fighting below. Cold wind brushes his skin like a sharp cut, carrying the scent of scorched metal and dry earth. In this world, where everything is as fragile as a taut thread stretched to its limit, this talented advisor knows full well: just one misstep, and a life ends.
Down there, a team is facing off against a pack of Demonic Beasts. They are no longer the simple creature from the apocalyptic war days. Those said beasts have evolved now, with metallic glossy hides, razor-sharp claws, and eyes glowing red like those of a true predatory species.
A tall Sentinel swings his blade to cleave an oncoming enemy in two, but his movements are growing clumsy, his breaths coming in gasps, his eyes showing only whites, and Yuta recognizes it right away: this man is losing control.
“Hey, calm down,” the teammate nearby shouts, trying to rush over for a closer look.
And from what Yuta knows, they are a pair of Angel and Guardian, in other words, mated to each other.
The spirit bond between them wavers, flickering like a flame about to snuff out in a storm that is struggling to flare back to life. But it is already too late.
The Angel collapses to the ground, his eyes turning pitch black, a growl no longer human escaping from his throat.
He's falling. Yuta clenches his fist tight.
The man turns his head, no longer able to tell friend from foe, his blade lunging toward his teammate. Another young soldier let out his painful scream, blood spraying from the wound on his shoulder as he topples to the ground and breathes his last. The whole team falls into chaos at once, scrambling to salvage the situation, but they are not calm enough to think of the right way out.
BOOM
Suddenly, a loud explosion rips through the sky, cutting the space short.
The squad leader, who is also the mate of that Fallen Angel, fires a sniper shot straight into the chest of the man losing control. The tremendous force sends The Angel crashing down, his eyes gradually returning to human's normal deep black, but he no longer draws breath.
Yuta turns his back because he does not want to see any more. This scene is all too familiar to someone who often observes brutal battles, but each time he witnesses it, the feeling is still like his chest being torn open in agonizing pain.
The thread connecting Sentinels and Guides is what keeps humanity alive, but it's also a sharp knife held to their throats.
A Guide loses their life, and their Sentinel mate will fall with no way to cure it. A Sentinel breathes their final breath, and the spirit of their Guide mate will shatter instantly and collapse completely, no different from sudden death right then and there.
And in this world, where the government system reigns and forces those Angels and Guardians to sacrifice for humanity, that balance grows ever more fragile, ever easier to shatter.
_
Safe Zone, Operations Room 127.
The light from the energy panels flickers weakly, the room wrapped in four cold white walls. Mark sits on a metal chair, his hand flipping back and forth over the old control panel. He is checking the logistics supply list, a job he has done hundreds of times. The work of a Class C Guardian, or more accurately, a flawed Guide not allowed to go into battle.
Mark Lee, a young Guide who just turned 21 not long ago, the one both the organization and the Nexus Council know as useless in combat, a Guardian who cannot heal any Angel unless they have perfect compatibility with him, that means 100%, nearly impossible to occur.
Whenever Mark performs healing, instead of soothing the Angels, he causes them headaches, dizziness, nausea, he even speeds up the process of them going mad. This leaves Mark completely desperate.
For three years since awakening as a Guide, the person with the highest compatibility to Mark is Johnny, a Class S Angel, with 93% compatibility. Yet even with compatibility that high, Mark couldn't perform any form of healing on Johnny. This has left the organization completely unable to help Mark. If that 93% number cannot even form a spirit bond, they fear that right now Mark truly cannot heal anyone at all.
For a Guardian, being unable to use their ability means losing everything.
"Mark hyung, you've checked that list three times already," Sungchan speaks up, his voice unable to hide the worry. "Is something wrong?"
The boy sits on the chair across from him, his brown hair tousled from just returning from a mission. As a Class B Guardian, Sungchan always tries to conceal his fatigue to appear professional in front of the older guys, yet the massive workload still makes it hard for him to relax.
Mark just smiles faintly, his eyes fixed on the control panel. "Everything's fine. Just... want to make sure there are no mistakes, that's all."
He does not want to admit that he is trying to avoid thinking about the mission that just happened in the Wildlands. The sight of that Sentinel falling, the Guide's anguished cry when forced to end their mate's life with their own hands, then both of them collapsing dead together, and even one Angel who lost his life because that mad teammate killed him.
Mark can never get used to tragedies like this, never, no matter how many times he has witnessed them.
Dongyoung steps into the room, his black uniform covered in dust and grime. As a Class A Guardian, Dongyoung always carries a stern look on his face, yet his eyes unconsciously soften when they land on Mark.
"You did great today," Dongyoung says as he draws near to ruffle Mark's hair. "Supplies got distributed right on time, the team had no logistics problems."
Mark nods, but deep down he knows full well, that's just hollow reassurance.
He is not allowed on the battlefield, not allowed to heal any Angel. A few failed tests were all it took for the organization to issue the ban: Mark cannot heal anyone, he can only handle odd jobs like managing supplies or assisting with logistics. It leaves him forever on the sidelines, watching other Guardians like Dongyoung, Taeyong, or Sungchan shine in their roles.
"Don't blame yourself too much," Sungchan consoles him, as if the boy can read Mark's mind. "You did everything you could, not everyone can keep calm in a spot like today."
"But I didn't do anything except stand there and watch," Mark replies, his voice trailing off. "If I could help everyone heal..."
Dongyoung rests a hand on Mark's shoulder, cutting him off: "Don't blame yourself, those unavoidable situations are always like that, no one can change them."
Click
The room door suddenly bursts open at that moment, Jaehyun strides in, his black uniform still bearing a few dried bloodstains, yet the presence of a Class S Angel burns hot like fire.
Jaehyun, much like Johnny, counts among the most skilled Angels in the Golden Blood organization, and both already had a mate.
Jaehyun will always find out a way to lighten the mood whenever he senses everyone growing tense, but this time, fatigue clouds his face.
"The mission's over," Jaehyun says in a low voice. "We lost three teammates, pair number 200... And... a rookie..."
Mark clenches his fist, his nails digging into his palm until blood wells up.
If I weren't this useless, things would be different, Mark thinks.
Mark recalls a time in the past when he tried healing, that was on Jaehyun, during a subjugation exercise, on orders from the superiors, because Jaehyun's mate was handling a more critical mission.
Mark and Jaehyun's compatibility was only 82%, so the Sentinel crumpled to the ground, clutching his head and howling in pain, his eyes engulfed in a horrific blank white that revealed signs of falling. From then on, though Jaehyun never blamed Mark, Mark always caught the flicker of guilt in this older guy's eyes whenever they crossed paths.
"Don't overthink it," Jaehyun says, picking up on Mark's unease. "You're not the only one feeling helpless today."
Trailing behind him into the room come three more: Johnny, Taeyong, and Shotaro. These three did not join this mission, but they seem to have caught wind of the three teammates lost, each one looks glum, none of their usual easy cheer in sight.
The entire squad has assembled fully in the small operations room. Johnny, Jaehyun, Shotaro, and their Guardian mates: Dongyoung, Taeyong, and Sungchan. Then Mark, sitting alone in the room's corner with the control panel clutched in his hands. Normally the vibe among them all stays relaxed and lively, but today alone, everyone feels downcast and drained from the fresh bad news.
"Johnny..." Dongyoung picks up on the spirit bond with his mate humming, he hurries over to the Sentinel with the strained look. "What's the matter?"
"The higher-ups just sent down a pretty important notice," Johnny sighs, he heads to the room's corner and slumps onto the small sofa.
Dongyoung tags along, he sits down next to him and gently strokes his arm. "Need a hand?"
"I'm good, you rest," Johnny says, shaking his head with a faint smile.
"What's the notice about?" Sungchan asks, curiosity lacing his voice.
"Dongyoung, Mark, Jaehyun, and Johnny," Taeyong says sternly, the presence of a team captain at once dominating the heavy air. "Gear up, we've got a patrol in The Unknown Land."
"Me? On patrol? In The Unknown Land?" Mark frowns as he lifts his eyes, a touch of oddity settling in. "Isn't there some mix-up?"
"It was my call," Taeyong says, glancing toward the room's corner. "The higher-ups are talking about demoting you, I had to bring you this time."
"D-Demote...? What did I do wrong...? What mistake did I make?"
Pitying looks turn toward Mark from everyone. They know the reason, this matter has been debated for ages, the organization even considered cutting Mark from the system once they realized he proves nearly useless in the field. And since no one sees a better fix for the issue, they all fall quiet, quietly backing Taeyong's choice.
"You didn't do a thing wrong," Johnny sighs, shaking his head. "Snap out of it and get ready, we are heading out this afternoon."
"That soon? Didn't you all just get back?" Shotaro blurts out in surprise. "Heading straight out without a break, is that alright?"
The captain issues the announcement in a firm tone: "This is an emergency patrol, Yuta just picked up a life signal in The Unknown Land. Put another way, if that's truly a survivor, it'll double as a rescue op."
All eyes shift to Taeyong, each face showing something different, though most register shock, Jaehyun alone holds his blank expression.
"How long since the last rescue?" Mark asks hesitantly.
"Two years ago," Taeyong answers.
"Two years..." The room turns thoughtful in unison.
The Unknown Land, a region that lies even beyond the Wildlands, stands as an area humanity has barely begun to probe. The Unknown Land amounts to little more than the Wildlands with a very low degree of knowledge and intel gathered, which prevents them from pinpointing what lurks within such zones. Plenty remains unknown to the organization in these parts, so patrols into The Unknown Land naturally rank as extremely hazardous, reserved for elite fighters, class A and higher.
Mark cannot fathom why they picked him to tag along, i'm just a small useless C.
Shotaro catches Mark's anxiety, he moves to his side and gives his shoulder a soft pat for comfort. "It'll be okay, probably..."
"I'll go, you guys don't worry," Mark says, determination lighting his eyes. "Don't forget, since I can't heal anyone, I threw myself into physical training to make up for it, so I'll be fine."
Once Mark grasped that his Guide abilities amounted to nothing, he dove headlong into Sentinel-level drills with wild abandon, boosting his fitness considerably in the process. Put differently, his self-defense skills outstrip those of most other Guardians, the very factor that earned Mark his class C rank despite he cannot use healing.
Taeyong clears his throat to draw everyone's focus, he speaks firmly once more to relay the news:
"Anyone tied to this mission, fall back and prep the supplies. In three hours flat, rendezvous at the Safe Zone's rear gate, grab some rest while you can." With that, the team captain turns on his heel to leave, also calling to his mate: "Jaehyun, come on."