The troop was promoted. The layer filed a resignation.

The Arsenal changes a tier, not the headcount

Evony’s current strategy guidance says troop tiers, counters and the attack or defence scenario should determine army composition; more troops alone are not the answer. It also warns that troop training competes with research, city upgrades and General development for the same resources. That is the useful official frame. Evony does not publish a current public Arsenal cost table or event-scoring rule.

Specialist documentation says the Arsenal unlocks at Keep 27, upgrades eligible T10-and-above troops one tier at a time, requires the target troop building level, and can use only troops inside the city. Wounded troops must be healed first. Power temporarily falls when the batch enters promotion and returns at the higher value when it completes. Confirm every condition in the live Arsenal before committing; the specialist guide was published in 2023, not handed down on a stone tablet yesterday.

A promotion keeps the troop count flat. Training fresh raises it. For a compact attacking account, that difference can protect ghosting capacity. For a layered defender, the same promotion can remove a useful tier and make the army less complete. “Higher” and “better for this account” are related. They are not married.

Set the protected floor before touching the slider

For one troop type and tier, record the eligible count E and the protected lower-tier floor P. The maximum safe promotion is:

Safe promotion U = max(0, E − P)

If the desired higher-tier addition is D, train at least D − U fresh when D is larger than U. The protected floor should cover every real job that would still exist tomorrow: march layers, a second attacking block, city defence, rally duty, monster work and any count needed to keep all troops within ghost capacity.

Worked example: an account owns 2.4 million T13 ground and wants 1.8 million more T14 ground. Its presets and defence plan still require 1.2 million T13. The safe promotion is 2.4M − 1.2M = 1.2M. Promote at most 1.2 million, then train the remaining 600,000 T14 fresh. The result keeps 1.2 million T13 instead of discovering after the timer ends that arithmetic also has a hospital.

Choose the method by account job

• Compact attacker or ghosting account: promotion can move an existing main block upward without increasing total troop count. Recalculate ghost capacity and reopen every affected preset first. Do not promote a support tier merely because it fits inside the Arsenal.
• Layered city defence: fresh training is the safer default when the lower tier still absorbs, triggers or fills a defined layer. Promote only the verified surplus. A defence is not improved by deleting a tier that the plan still expects to exist.
• Monster or rally specialist: promotion can be sensible when a higher tier reaches a tested target and the lower tier has no separate rally, joiner or stamina-saving role. Compare like-for-like reports. A larger power number is not a free wounded report.

Fresh player discussion from October 2, 2026 follows the same split: players with compact or ghostable armies describe promotion as useful during a top-tier transition, while layered defenders prefer to keep older tiers and train new troops. Those are account observations, not a universal combat test.

Compare the live screens, then test the event

1. Write down E, P and D before opening the Arsenal. If P is guesswork, stop and audit the presets first.
2. Compare the live resource and speedup cost for promoting U troops with training the same number of the target tier. Ignore resources already spent on the lower tier; they are sunk. Do not ignore the lower tier’s remaining tactical value.
3. Confirm the target Barracks, Archer Camp, Stables or Workshop level, the eligible tier, the in-city count and Hospital status.
4. Use a small batch when event points matter. Historical specialist guidance says Arsenal completion is not Troop Training and may instead register through power gain, but no current official public rule was found. The live event wording and a tiny batch are better evidence than an old confident sentence.
5. After completion, reopen the affected march, defence and ghosting presets. Check counts rather than trusting saved percentages.

Do not start a large batch only because a Consuming Return or Power Increase event is visible. First verify which action the event counts, when it scores, and whether the reward is worth changing the army. A reward chest is not a troop doctrine, although it has been known to dress for the part.

Evidence limits

Official Evony guidance supports role-specific troop composition and the resource trade-off, but it does not publish current Arsenal mechanics, exact costs or event scoring. The Keep 27 unlock, T10-and-above eligibility, target-building requirement, in-city requirement and temporary power change come from specialist documentation published June 15, 2023 and checked against accessible current references. The compact-account and layered-defence split is supported by a current player discussion, not controlled testing by Kat’s Quiet Keep. Live client wording, current costs, server rules and event details take priority.

Sources: official EvonyOps strategy guidance, updated 2026-10-26 and reviewed 2026-10-30; Theria Arsenal guide, published 2023-06-15 and reviewed 2026-10-30; player discussion of Arsenal use for compact and layered armies, 2026-10-02 and reviewed 2026-10-30.

Evidence reviewed 2026-10-30. Official strategy guidance, older specialist mechanics, current player observations and editorial arithmetic are separated. No current official cost table, event-scoring promise, private report or independent combat test is claimed.

— Kat