Steel and Sundering Steel in Arknights: Endfield (Materials and Weapon Explained)

Steel shows up in two very different ways in Arknights: Endfield. In the AIC factory it exists as a processed material and as a device part, while in combat it appears as Sundering Steel, a 5★ sword. The names are similar, but they sit in completely different systems: factory production versus character gear.

Steel material in Arknights: Endfield (AIC Product)

Steel is classified as a 3★ AIC Product with the type “High Quality Material.” It is created by refining Dense Ferrium Powder and is described as a high‑grade industrial metal. In the world’s fiction, Steel made by Endfield Industries goes through multiple processing stages and is rated as a Grade 2 reference metal within the Talos‑l1 blight resistance standards, which effectively marks it as a robust, contamination‑resistant alloy used for serious infrastructure and equipment.

In practical terms, Steel is not an end goal resource. It exists to be fed into further processing steps. It can be turned into more specialized AIC Products and intermediate parts that then appear in construction or higher‑tier crafting.

Steel Part (processed device component)

Steel Part is another 3★ AIC Product, but it is tagged as a “Device Part” rather than a bulk material. Instead of being refined directly from ores or powders, it is explicitly manufactured from Steel. That makes it one step further down the production chain: Steel is your treated metal stock, Steel Part is what you get once that stock has been machined into usable components.

Steel Part’s description emphasizes its broad applicability. It can be consumed in recipes for other items or placed into construction requirements when building facilities in the AIC system. Anywhere the game needs a generic mechanical component with decent durability, Steel Part is a likely candidate.

How to get and use Steel and Steel Part

Both Steel and Steel Part live inside the AIC (factory) loop rather than as combat drops you equip directly. They appear in the AIC Products category alongside other refined materials like Dense Ferrium Powder, Ferrium derivatives, Cryston items, Liquids, and powders.

The in‑game factory UI for each of these products provides a “crafting tree” and a “usage” view. For Steel and Steel Part, those views summarize two things: which inputs you need and which recipes or facility plans consume them. The interface lets you toggle between how‑to and usage with on‑screen buttons in the upper left of the item detail panel.

Even when specific recipe lines are not visible yet, the classification already tells you how to think about them. Steel is a mid‑tier, upgraded metal. Steel Part is a generalized device component derived from that metal. As you unlock more AIC blueprints, they start to slot naturally into weapon manufacturing, facility modules, or higher‑grade parts.

Sundering Steel (5★ sword weapon)

Separate from those factory items, Sundering Steel is a 5★ Sword weapon. It is not a material and does not sit in the AIC product grid. It is a piece of combat gear that you equip on sword‑using operators to raise attack and add weapon skills.

Sundering Steel is obtained through the Acquisition Center’s Arsenal Exchange. Within the weapon database it is identified internally as wpn_sword_0005 and is grouped among other swords such as Eminent Repute, Grand Vision, and Thermite Cutter.

The weapon description frames it as elite Endfield‑manufactured equipment. Mechanically, its defining feature is a stress‑triggered energy storage mechanism, represented in‑game by an ATK buff that stacks when the wielder applies physical status.

Sundering Steel base stats and scaling

Swords in Endfield scale with level, and Sundering Steel follows the same pattern. Its base ATK starts low but grows into a strong mid‑to‑high tier stat line for a 5★ weapon.

Alongside raw ATK, the weapon gains flat Agility and a percentage Physical DMG Dealt bonus as its skill rank increases. These bonuses are baked into its weapon skills table and grow steadily from rank 1 up to rank 9.

Sundering Steel weapon skills (Aggro, damage, and stacking ATK)

Sundering Steel carries three core stat boosts at all skill ranks: an Agility increase, a Physical DMG Dealt increase, and a unique skill named Combative: Anthem of Cinder. The first two are straightforward. The third is what turns the sword into a sustained DPS tool for physical damage dealers.

Combative: Anthem of Cinder always has two pieces. The first is a flat ATK bonus that climbs as you raise the weapon’s skill rank. The second is a conditional ATK buff that stacks when the wielder applies a Physical Status.

Each time the wielder inflicts a Physical Status, they gain one stack of Anthem of Cinder for 20 seconds. The effect can stack up to two times, each stack tracks its duration separately, and the trigger has a short internal cooldown of 0.1 seconds. Once both stacks are active, a rank 9 Sundering Steel can be providing a very large temporary ATK increase on top of its permanent bonuses.

In play, that design rewards operators with frequent physical hits and status interactions. They bring out the sword’s full value by keeping both stacks refreshed and exploiting the high Physical DMG Dealt percentage while the buffs are active.

Tuning Sundering Steel (level caps and material costs)

To unlock Sundering Steel’s stat curve you need to tune it at the weapon enhancement screen. Tuning raises the weapon’s level cap in brackets (20, 40, 60, 80) and consumes a mix of upgrade materials plus T‑Creds.

These materials are all part of the broader progression economy. Cast Die and Heavy Cast Die act as generic weapon upgrade tokens, while Kalkonyx, Auronyx, Umbronyx, D96 Steel Sample 4, and Wulingstone are more specialized items you gather over time. Because later ranks are much more expensive, it is normal to keep Sundering Steel at a mid tuning level early on and only push to higher caps once you have a stable material income.

Lore context for Sundering Steel

Beneath the numbers, Sundering Steel carries a substantial flavor text monologue. It addresses someone who once stood watch over smelting furnaces, now working as an arsenal engineer at Endfield after leaving a previous post at a Fort. It describes how that engineer designs weapons influenced by years of real combat, folds in research from Endfield’s technology, and mentors a younger girl who is fascinated by stories of unsung heroes.

The story touches on guilt, desertion, and the reluctance to pass on swordsmanship to someone who already has the protection of Endfield’s arsenal and her parents. It ends with a nudge from another voice, urging the engineer not to make the girl sad, even as he considers transferring back to field service. The details connect the weapon’s seamless design and engineering cues to the character’s background, reinforcing the idea that Sundering Steel is more than a stat stick: it is a product of lived experience and moral conflict inside Endfield Industries.

Seen together, Steel, Steel Part, and Sundering Steel show how Endfield ties its factory layer and combat layer thematically through industrial metals. Steel and its derivative parts support infrastructure and production in the AIC system, while Sundering Steel translates that same industrial expertise into a high‑performance weapon for physical damage operators.