Umbral Monument is the first permanent high-difficulty combat mode in Arknights: Endfield, designed to give players who have finished the main story progression a recurring challenge with meaningful rewards. It launched its first series, Those Forsaken by the Land, on February 12, with a second series called Inorganic Construct following on February 26.
Quick answer: Umbral Monument unlocks after you complete Chapter I Process II: Paving the Way and reach Authority Level 30. You only need one team of four operators per stage, and clearing Normal mode earns all Oroberyl rewards — Agony mode is purely for the trimmed medal and bragging rights.
Unlock Requirements
You must finish Chapter I Process II: Paving the Way in the main story and reach Authority Level 30 before Umbral Monument appears. This puts it squarely in mid-to-late-game territory. If you've already cleared the currently available story content and have been building your operators, you should meet both conditions comfortably.
Structure and Difficulty Modes
Umbral Monument is organized into series, each containing multiple combat stages. Every stage offers two difficulty tiers.
Normal mode allows you to bring Tacticals (consumable healing items) into battle. It has a 10-minute timer per stage, and clearing within that window is the only requirement — there are no sub-timers or speed-based reward tiers. Finishing all Normal stages in a series earns an engraved medal.
Agony mode unlocks for each stage after you clear its Normal version. Enemies hit harder, additional stage mechanics come into play, and Tacticals are completely disabled. Clearing all Agony stages in a series earns a trimmed engraved medal, which functions as a skill trophy. During closed beta testing, the time you took within the 10-minute window did not affect rewards at all — spending nine minutes and clearing in the last sixty seconds still counted as a full clear with the trimmed medal.
Each stage features unique gimmicks and enemy mechanics rather than being a straightforward stat check. Before entering any fight, you can review recommended levels, stage mechanics, and detailed enemy intel to plan your team composition accordingly. One stage, for instance, applies constant poison damage but grants an AoE heal mechanic when your team receives healing, making a dedicated healer almost mandatory.
Team Requirements
Each battle allows a maximum of four operators. Only one team is needed per stage — there is no multi-team rotation like some other gacha endgame modes require. That said, different stages favor different operator archetypes. In beta, the first stage leaned toward AoE damage (favoring operators like Laevatain), the second rewarded single-target burst, and the third suited different playstyles entirely.
Whether a single well-built team can sweep every stage depends on difficulty. In beta, Normal mode was lenient enough that one strong team could handle all stages without swapping. Agony mode may push you toward adjusting your lineup, especially since Tacticals are banned, and self-sustain becomes critical. Operators with built-in healing, like Ember, become significantly more valuable when you can't pop a healing consumable mid-fight.
Rewards and First-Clear Bonuses
Completing Normal mode for a series grants all obtainable Oroberyl rewards for that series. This is a notable design choice — the hardest difficulty does not gate your gacha currency income behind it. Agony mode rewards are limited to the trimmed medal and potentially some extra upgrade materials, but the premium currency is fully accessible at Normal difficulty.
First-time clears of each stage also award one-time resources:
- Mark of Perseverance
- Advanced Cognitive Carrier (operator EXP material)
- Arms INSP Set (weapon EXP material)
- Protohedron
Monumental Etching — The Biweekly Limited Event
Alongside each Umbral Monument series, a limited-time event called Monumental Etching runs for approximately 14 days. During this window, you can complete additional challenges within Umbral Monument stages to earn Oroberyls. Once the Etching period rotates out, those specific Oroberyl rewards are gone.
Each Etching cycle awards roughly 2,400 Oroberyls. With two cycles per month, that adds up to about 4,800 Oroberyls monthly from Umbral Monument alone — approximately 10 pulls' worth of gacha currency on a recurring basis.
The 10-Minute Timer
Every stage has a 10-minute countdown. If you fail to defeat all enemies before it expires, the stage ends in a loss. However, the timer serves only as a fail condition — it does not scale rewards. There are no tiered reward brackets based on clear speed.
In practice, 10 minutes is generous. During beta, players running full-defender compositions with minimal DPS still cleared stages with minutes to spare. The timer exists primarily to prevent indefinite stalling strategies rather than to function as a strict DPS check. That said, Agony mode's increased enemy health pools and additional mechanics will eat into that buffer more than Normal mode does.
Umbral Monument in Endfield's Broader Endgame
Umbral Monument fills the combat-focused endgame slot, but it is not the only late-game activity Hypergryph appears to be building out. Etchspace Salvage serves as an exploration-focused endgame mode (currently available through Area 3, with infrastructure for up to Area 6 already visible in-game). A third mode called Delver of the Cryptic is listed on the version roadmap with a puzzle focus. All three are categorized as permanent events rather than limited-time content, suggesting they will expand with future version updates.
For players worried about resource pressure, the key takeaway is straightforward: build one strong team with a healer first. Normal mode clears grant full Oroberyl rewards, Agony is optional prestige content, and you only need four operators per fight. Prioritize claiming Monumental Etching rewards before each two-week window closes, since those Oroberyls do not come back.
