SI LORE: THE ANCIENT GOD WHO SKIPS PAPERWORK

Si is the last spark of Sui, an ancient god of Yan, and the newest 6-star operator in Arknights Endfield. The first thing her files record her doing with that power at work is sending a painting of herself to her own job interview.

Her profile records and voice lines read like a case file on a cryptid: seen in two places at once, impossible to schedule, extremely powerful, and occasionally caught with a hole in her shield. Underneath the comedy is a stranger story about where she came from, and about how long she has known you.

How we checked this. Everything below comes from Si’s six profile records and her voice lines in the official English localization, read from the current game data on 15 October 2026. Quotes are the game’s own English text. Where the files only hint at something, we say so. The images are scenes from our own Short about her, built from the same files.

Endfield Hub is a fan-made resource and is not affiliated with Hypergryph or Yostar.

TL;DR - Key Points

• Si is a Feranmut Proxy tied to the Hongshan Academy of Sciences (HAS), recruited to Endfield on the Endministrator’s personal recommendation. She calls herself an “honorary Endfielder”.
• She sent a painting to her onboarding. It answered every question and signed the forms. The real Si showed up afterwards, wiped ink off the HR assistant’s screen, and judged its reaction “not interesting enough”.
• She is almost never where you expect. Two operators swear they saw her at the same moment, thousands of miles apart: winning a witchcraft staff auction above ground, and drunk with Snowpriests below it.
• Her powers are real and slightly unreliable. Weapons forged from thin air, paintings that come to life, and the occasional shield with a hole in it, which she calls “a sample piece”.
• She is the last fragment of Sui. Sui’s twelve proxies sent that fragment to Talos-II to become someone new. Her review of Sui: “the worst Feranmut. Ever.”
• She knew you before you forgot. Her voice lines mention a promise from ten years ago that the Endministrator no longer remembers.

Who Is Si?

Si’s basic file is short and evasive. Codename Si, female, authenticated by the Hongshan Academy of Sciences, born September 15. Race: undisclosed. Oripathy negative. Combat skill is rated Excellent, tactical acumen Standard, and her physiological strength is redacted to two black squares. The one surprising line is Originium Arts assimilation, rated Flawed.

Her Human Resources summary describes her as “a Feranmut Proxy with no formal employer” who provides expertise in “the theoretical research and practical application of Feranmuts”. In battle she is a 6-star Cryo Supporter on a greatsword. Her own view of the job, from a promotion line: “I’m just an honorary Endfielder, so don’t expect me to do everything. Also, Endfield better be as interesting as you claim.”

The Painting That Did Her Job Interview

The HR summary is written by Martin Marvin Malen, an assistant in the HR Division who refers to his own “processing module”, “self-diagnostic log” and “display”. Si arrived on Dijiang as agreed, answered every question, signed the paperwork, “and disappeared the moment the process was complete”. His processing module classified it as an unforeseen incident and raised an alert.

“A short while later, Si walked back into the office, wiped a drop of ink from the center of my display, and mumbled, ‘Interesting … but not interesting enough.’” The Si in the chair had been a painting of herself. She wanted to see how the assistant would react, and “judging from her remark, my response wasn’t quite what she had hoped for.”

Malen took it well. He called it “a harmless prank” and recommended that his HR colleagues “take every chance to interact with her. We may eventually discover a pattern to her shifting moods.”

Have You Seen This Proxy?

File 1 picks up the problem: after joining, “almost no operators ever met Si”. HR even asked the Endministrator to talk her into finishing her onboarding, apparently without success. Then a logistics operator shared a table with a stranger at a hotpot promotion in Wuling City, sampling broths like Lime and Bitter Gourd Stock and Fish Maw and Slug Pepper Stock. The stranger was there “to pick up a few tricks for the chef at her inn”. The operator praised her “remarkably refined taste for someone so young”, and Si, delighted, quietly paid the operator’s bill too. Only later, spotting her photo in HR, did the operator work out who it was.

After that the sightings piled up: the Chubby Lung launch in Wuling City, La Fantoma’s robotics experience center, and more. Two operators argued about one sighting in particular. One swore she was the “mischievous bidder who scooped the final item” at Seš’qa’s witchcraft staff auction. The other swore she was “the mysterious guest who got drunk among Sami’s Snowpriests”. Same time, “thousands of miles apart, one above ground, the other below.” The file’s conclusion: she is “less like a secluded Feranmut Proxy and more like an energetic child who simply can’t stay home.”

Three pieces of advice close the file:

• Argent Flow: avoid the words “child” and “young”. “I’m nearly as old as civilization itself on Talos-II. You’re all just kids to me.”
• Arcane: “When it comes to critical matters, please trust the Proxy.” She also does not like having her abilities questioned.
• An unknown guest: “If she starts throwing a fit, just go get the Endministrator.”

So “young” gets you a free hotpot from a stranger and a lecture from a coworker. Context matters.

The Skills List That Crashed HR

She did fill in one form herself, and it went badly for the form. “The Endfield HR database has issues. For the ‘Skills’ section, I listed twelve items, including martial arts, literature, painting, metallurgy, law, gardening… and then it just threw an error. What, too many skills?”

She has a ready answer for anyone who doubts the list: “Occasionally failing at something doesn’t take those skills away. You’d better give me an explanation of what’s going on.” Twelve skills is not a random number for her, as the last section of this post shows.

Powers, and the Hole in the Shield

File 2 is a set of training logs from the Yinglung Special Task Force (YSTF), the HAS unit she helped found. Log III: a scheduled meeting with new recruits, and “the Proxy was absent without prior notice”. Log VIII: a lecture on Feranmut powers, also absent, and on short notice she sent Ye Minghe, Captain of Pacified Skies of the Imperial Guards, and the Endministrator to teach it for her. In a voice line she floats the same idea again: “Endmin, why not take my place and go teach them for me?”

Log XXI is the one where she turned up. The location is listed as “a scroll painted by the Proxy on the spot”, and the session ran more than three hours over. Her “little tricks” included moving stone and timber into “a garden no one could escape”, forging shields and greatswords out of thin air, a seed that “sprouted, withered, and sprouted again within moments”, ink paintings that came to life, and “turning squares into circles”.

Then the mishaps. “On rare occasions, a giant shield would inexplicably contain a large hole, or the painted sun would become nothing more than an ink blot suspended in the sky, steadily dripping ink.” Her cover-ups: “an exaggerated cough, abruptly painting a river and declaring an impromptu exercise in river-crossing combat, or simply ending the session then and there.”

She has her own version of the shield story. “Just like this shield I’m holding… What? A defective pore…? AHEM. Oh yes, this is just a sample piece. Tiny flaws are expected, and definitely unrelated to the mastery of my powers.” Arcane, who signed the log as YSTF Task Leader, is kinder: the Proxy “inherited the Powers of the Feranmut ‘Sui’ and all twelve of its proxies only recently”, and “possessing a skill is not the same as mastering it.”

The Wings She Drew Herself

“My wings are pretty, right? When I was young, I dreamed of them sprouting and spreading, so I drew them on my back after I woke up.” Her sister disagrees about their purpose. “She said I use them in fights to look intimidating. Hmph. That’s a baseless accusation. I mean, who even does that? So childish!”

She also cares about them. Her line for a new piece of gear: “It even takes my wings into account… Ahem. N… Not bad, but I won’t be nice just because of this.” When she is hit: “Did they soil my wings?”

An Inn Inside a Painting

Si runs an inn, and the inn is inside her scroll. Her staff are not great at their jobs. “Job Rusher is always slacking off, Speed Dasher is so big he could hardly move, and Loud Speaker greets guests so softly you’d miss it if you blink. It’s been decades, and I gave up trying to fix up their habits.” They had nowhere else to go, so she added them to the scroll. “I can send them away… but I prefer my inn messy than quiet.”

The inn is getting popular enough that the staff want a suggestion board, and she wants the Endministrator to sort the suggestions first. She also sends her best Ink Spirits to pick tea from a cliff, “a decade of work, all packed into this little jar”, which leaves both of you with ink on your teeth. And she wants your help winning chubby skydrummer plushies at Wuling’s “Sketch and Guess” game, which “can’t be played alone”. You draw, she guesses. “Do I look like the sort who cheats in games?”

The Wrong Gift

Her gift line is short and complete. “Here. A little gift for you, just something I doodled. Don’t get too exci… Ah, wrong one! That self-portrait is just practice. GIVE IT BACK!” (The “#47” on our drawing is our joke; the file does not number them.)

When she gives you a painting on purpose, the signature is the point. “What I drew isn’t important. It’s my seal that matters! And don’t you ever forget my name again!” She will also stamp your hand with her tail, “and you better not rub it off until I decide to stamp you a new one.”

How the Yinglung Special Task Force Got Its Name

File 3 explains the Sui Regulator. In Yan, the original Sui Regulator was set up after the Great Hunt to watch the dormant Sui, and its Candleholders monitored his twelve proxies, a relationship that stayed tense “for nearly a thousand years”. At HAS the name was reused for an intelligence and technical support group that develops Feranmut-based technology, and Si helped found both it and the YSTF under it. “To the Sui Regulator, Si is more like a quirky advisor.”

The file then quotes a letter from one of her brothers: “I fear even the breadth of Talos-II may one day prove too confining for my younger sister… Thus have I sent her to Hongshan to broaden her horizons, trusting that Tianshi Tan will look after her.” Si’s reaction: “That’s all my brother wrote?” The Tianshi’s: “Your brother warned me that if anyone here so much as upset you, he’d come knocking on my door. At this point, I’m just glad he didn’t send a knife along with the letter!”

He suggests calling the new office the Si Regulator. She refuses: “The Si Regulator sounds terrible. Like the whole place exists just to keep an eye on me.” The old name stays. For the task force he proposes “the Yinglung Special Task Force”, since “this unit only exists because of you”. Her answer: “Cool! I love it!”

Where Si Came From: The Last Spark of Sui

File 4 changes tone. “When the dust finally settled, Feranmut Sui never awoke again.” His body was gone and his will sank into silence. But a fragment of his consciousness remained, “like morning dew gathering upon fresh leaves”, and fell. One proxy gathered it up. It could not speak or use any power, and it “flickered like a candle flame, bright and perfectly pure.”

The proxies could have erased it “with a single thought”. Instead it asked them three questions: “Who am I?” “Where am I?” “Who are you?” They decided that if it knew nothing of Sui’s past, “then she was no longer Him”, and sent her through the Cosmic Gate to an unknown world to find her own answer. The file ends on a slip: “they packed far too much. They kept stuffing things into my … no, into its hands. After that … well, that’s another story.” The file does not say who wrote it.

Si’s own summary is less poetic. “Sui is the worst Feranmut. Ever. Even in sleep, He won’t stay still, always scheming to make things hard for Yan with his twelve proxies.” She owes her existence to the proxies bringing “the last bits of his soul to Talos-II”, but “we’re different. There is nothing between us, one way or the other. The debt’s settled and it’s as clear as day.”

For the wider mythology of Sui, the Great Hunt and the proxies, see what a Feranmut is and our earlier look at Si as the 13th Sui Proxy.

The Siblings She Doesn’t Miss

She grew up around her siblings, playing Weiqi, listening to them talk and practising reading, calligraphy and painting at night, with the three of them traveling Talos-II together, “but soon they sent me off to Hongshan”. She understands why. “But you can’t just leave your little sister somewhere and barely visit her…”

Looking out of a window on Dijiang: “Who said I miss my siblings? Don’t look at me like that…! Sigh Fine. Maybe I miss them a little bit. Just a bit…” After a game of Weiqi she insists her brother is still “the best player on Talos-II”, then gets caught: “What? This is the third time I’ve brought up my siblings this month?” She also keeps the inn ready for them. “What if they come home and see this mess? You’re gonna get me in trouble!”

She Knew You Before You Forgot

The most interesting thread in her voice lines is the Endministrator. “So, that promise ten years ago. You gonna make up for it?” She painted a portrait of the Endministrator ten years ago, “but you weren’t wearing anything on your face back then.” She complains about the habit of “working yourself into the ground and then sleeping for ten years”, and calls the Endministrator “Dork-Min” for trying to travel before recovering: “I was hoping that stupid habit of self-abuse disappear with your memories.”

Her Trust line is the closest she comes to saying it plainly. “Back then, you made uninvited visits when I was alone. You had a way of turning ridiculous ideas into comforting words… Fine. I know my words won’t bring back any of your lost memories right now. But if you dare to forget anything ever again, I won’t talk to you for the next ten… no, one hundred and fifty years!”

What the Files Don’t Say

• What the promise was. She brings it up but never states it.
• Who wrote File 4. The “into my … no, into its hands” slip suggests a first-person narrator. The file does not name one.
• Which sibling wrote the letter. File 3 says only “my brother”. Her voice lines mention a brother who plays Weiqi and a sister who teases her about her wings.
• Her age. She claims to be “nearly as old as civilization itself on Talos-II”, while File 4 describes a consciousness only just beginning. Both can be true; the files do not reconcile them.

Further Reading

• Who is Si? The last fragment of Sui: how her twelve siblings killed Sui in the first Arknights and sent her to Talos-II, told from her File 3.
• Si build guide and best Si teams, plus her operator page.
• Si showcase: skills and profile.
• Arcane lore, the YSTF Task Leader who signed the training logs.
• Perlica lore, the “miss little supervisor” Si scolds for pulling all-nighters.
• Feranmut proxies and the Wuling hegemony.
• Endfield lore hub: every operator backstory and our story Shorts.