Arknights: Endfield Sanctuary of Ink: Si & Argent Flow Guide

Arknights: Endfield is dropping two new 6-star Operators in its Sanctuary of Ink update on October 15, and if you have been saving pulls, you have a real decision to make. This GameMarket.gg breakdown focuses on the two headliners the banners are built around: Si, the ink-and-brush support tied to the new painted world, and Argent Flow, the mounted Electric Guard who charges in on horseback. They arrive on separate banners, so most players will not pull both, which is exactly why the big question is who you are gunning for, or whether you skip the whole patch. Here is who each Operator is, how they play, and how to decide where your pulls should go.

Two new 6-stars, one big choice

The patch is split across two banner phases, each built around one new Operator. Si headlines the first phase from October 15, while Argent Flow takes over from November 5, with a Tangtang RE-Factor rerun slotted in between. That gap gives you time to regroup resources, but committing to both new units back to back is a serious ask for free-to-play players.

There is a nice sweetener for both pulls, too. Each new Operator comes with a seven-day login event that grants five free pulls, so simply logging in during each banner nudges you closer to a copy. It is a small but real head start that makes trying your luck on either banner less painful.

The timing also matters beyond the banners, because Sanctuary of Ink is a milestone patch. It launches on October 15, 2026 alongside the game's Steam release, so a wave of new and returning players will be jumping in at the same time. That makes this a natural moment to invest, since the community will be at its most active right as these two Operators go live.

The update also builds its new content around Si specifically, which is worth knowing before you choose. The headline addition is a new map set inside a painted world, where you use Si's Miracle Brush to reshape the environment and open new paths, backed by fresh story, a new boss, and events like a countryside inn you manage and cook for. None of that requires pulling her, but it does mean Si is woven into the patch's identity in a way Argent Flow is not, which may sway fans who want to feel connected to the story they are playing.

Si, the ink and brush support

The "brush expert" from the teaser is Si, and she is the face of the whole update. She is a 6-star Cryo Supporter whose kit buffs both Cryo and Heat teams while still dealing damage herself, making her a flexible enabler rather than a pure healer or pure DPS. Her thematic tie to the Miracle Brush and the new painted map is why the version is named after her.

Her standout mechanic is what makes her interesting on the battlefield:

• Class & role: 6-star Cryo Supporter (support plus damage).
• Element: Cryo, with buffs that boost both Cryo and Heat damage.
• Signature mechanic: her Ink Souls and Artful Intent debuff create a linked target on an enemy that extra attacks and effects can hit.
• Ultimate: amplifies Cryo and Heat damage for the entire team.
• Banner: Phase 1, October 15 to November 5.

That dual-element support is her big selling point. Because she lifts both Cryo and Heat teams at once, she slots into more comps than a narrowly tuned buffer would, and teams built around Heat carriers stand to gain a lot from her. If you run or want to build around those elements, Si is a strong, versatile pickup.

Supports also tend to age well in games like this, which is part of her appeal as an investment. A good carry can be power-crept by the next shiny DPS, but a flexible buffer who boosts two whole elements stays useful across many future teams, often long after the banner is gone. That makes Si a safer pull for players who want lasting value rather than a unit tied to one specific comp, and her linked-target mechanic gives her a bit of damage identity so she never feels like dead weight on the field.

Argent Flow, the mounted guard

The "war-horse expert" is Argent Flow, and he could not play more differently. He is a 6-star Electric Guard who fights mounted on his galloper, Nuli, trading Si's support role for aggressive, high-mobility frontline damage. If you prefer being the one dealing the big hits rather than enabling them, he is the pick aimed at you.

His kit is built around setting up and cashing in debuffs:

• Class & role: 6-star Electric Guard (frontline DPS).
• Damage: a mix of Electric and Physical.
• Signature mechanic: applies Electrification, Vulnerability, and Sunderization, then detonates them for bonus Electric damage.
• Playstyle: mounted charges and high-mobility attacks alongside Nuli.
• Banner: Phase 2, from November 5.

What makes him appealing is that mounted mobility plus debuff-detonation gives him both reach and burst, and his Sunderization effect also supports Crush-focused teams. He is the flashier, more hands-on of the two, rewarding players who like to dive in and control the pace of a fight.

His mobility is also a genuine gap-filler on many accounts. A mounted Operator who can close distance fast and reposition mid-fight plays very differently from a stationary damage dealer, so he adds a tool the roster may be missing rather than duplicating a role you already have. For players who find turtling up boring, Argent Flow is the kind of aggressive, skill-expressive unit that keeps combat engaging run after run.

Si vs Argent Flow: how they differ

Side by side, these two fill opposite roles, which is what makes the choice about playstyle rather than raw tier. Si is an enabler who makes your whole team hit harder, especially Cryo and Heat squads, and she rewards players who enjoy building a comp that snowballs around a strong support. She is the safer long-term investment if your account needs a flexible buffer.

Argent Flow is a self-sufficient damage dealer who wants to be in the thick of the fight, applying and popping debuffs for burst Electric damage. He appeals to players who would rather carry a fight themselves than set the table for others, and he brings a mobility and aggression the roster does not have much of.

Where you are in the game should steer the call, too. Newer players and anyone jumping in via the Steam launch often get more mileage from a universal support like Si, since she instantly makes a thin roster punch above its weight. More established accounts that already have solid buffers may prefer Argent Flow to add a new damage and mobility option they lack. Matching the pull to your account's stage is just as important as matching it to your taste.

The honest truth is that neither is strictly "better," because they do not compete for the same slot. A support like Si and a carry like Argent Flow can even end up on the same team, so the real question is which gap your roster has right now and which style you actually enjoy playing. Pulling the unit you will use every day beats chasing a name you will leave on the bench.

So, pull or skip?

Here is the practical way to decide:

• Pull Si if: you want a flexible support, you run or plan Cryo or Heat teams, or you simply love the ink-and-brush theme of the update.
• Pull Argent Flow if: you want a mobile, aggressive Electric carry, you enjoy debuff-detonation combat, or your roster is light on frontline DPS.
• Skip (or wait) if: neither fills a gap you have, you are saving for a future unit, or your pulls are too limited to commit, since the five free pulls per banner still give you a shot without spending.

The bottom line is that Sanctuary of Ink offers two genuinely distinct Operators rather than two versions of the same thing, so the smart move is to match the pull to your playstyle and your existing team. Decide whether you want the brush or the war-horse, use those free login pulls either way, and go into October 15 knowing exactly who you are aiming for.

If you want to make the most of the new banners, you can explore trusted Arknights: Endfield accounts to start with a strong roster, save time clearing content with reliable Arknights: Endfield hourly services, or push through the toughest stages with dependable Arknights: Endfield boosting.

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