Region Resonance

The per-region difficulty ladder — one shared level ladder for every region, frontier kill quotas, gold and crystal fees, the applied-Resonance dial, and the Magic Find / material / Key payoffs.

After clearing the final dungeon — the Throne of Endless Night in the Dark Citadel, where the boss Theron falls — you unlock Region Resonance: a per-region difficulty ladder that you raise by farming, then dial up or down whenever you like. Resonance I opens for free in every region the moment Theron falls; you only have to pick it on the map.

Resonance is not a run you start. It is a permanent setting on the region itself, and it climbs as a byproduct of normal idle farming.

What Resonance does

Every region carries a Resonance level from 0 to 10, displayed as I–X. From Resonance I on, every region runs on the same level ladder: the region’s top combat tile sits at level 110 at Resonance I and climbs +10 per level to 200 at Resonance X. The region’s other tiles keep their distance below its top tile:

effectiveRank = baseRank − regionTopRank + 100 + 10 × appliedResonance   (applied ≥ 1)
effectiveRank = baseRank                                                 (applied = 0)

So a Parched Grasslands tile and a Dark Citadel tile at the same Resonance fight at the same level — and since enemy strength, resistances and loot all follow the level, they are the same fight. The only thing the region still decides is the element of its enemies’ elemental attack. Enemy level follows effective rank, so it climbs past the hero cap of 99.

Resonance applies to combat tiles only. Dungeons and the Endless Delve are untouched by it.

The resistance tax

Rank is not the only thing Resonance changes. While you stand on a resonance-scaled tile, all four elemental resistances drop by 10% per applied level:

fire / ice / lightning / poison −= 10% × appliedResonance

That is −50% at Resonance V and −100% at Resonance X, subtracted from your uncapped gear + skill total before the +75% cap is applied. Your resistance floor is −75% — and negative resistance is not merely “unresisted”: it amplifies the elemental damage you take, so a fire rider against −75% fire resistance lands for 175% of its roll.

Physical damage has no such component; only the four elements are taxed. The same guards as rank scaling apply — the malus only exists on cleared combat tiles of a region with applied Resonance ≥ 1, and never in dungeons or the Endless Delve. Dial the region down and the tax goes with it (along with the payout). Echoed dungeon runs and the Brood Matriarch set their own fixed penalty instead (see Echo Ascension).

Practical consequence: deep Resonance is a resistance check, not just a damage check. Overcapped resistances that looked wasted at Resonance 0 are exactly the headroom that keeps you alive at Resonance VIII+.

Unlocked vs. applied

Each region tracks two numbers:

Value	Range	Meaning
Unlocked	0–10	The highest Resonance you own for that region — I for free after Theron, the rest purchased. It never goes down.
Applied	0–unlocked	The level actually in effect right now — a dropdown in the region map view. Off (0) until you pick a level.

Everything keys off applied: effective rank, enemy level, the resistance tax, Magic Find, material drop rate, and the Key chance. Farming below your unlocked level is the comfortable mode — you still get the full payout for that difficulty, you just make no progress toward the next step.

The dropdown lives in the region map view (top-right of the map) and can only be changed while combat is inactive. If you open the map mid-fight it is read-only until you stop.
Buying a step sets applied to the new unlocked level. Dial it back down immediately if you want.
Uncleared tiles always fight and reward at their base rank, whatever the region’s applied Resonance is.

Raising a region’s Resonance

Resonance I is free. Going from level L to L+1 after that takes two things:

Fill the kill counter. You need 1,000 + 250 × L kills in that region, and only kills made at your highest unlocked Resonance count — the frontier. Dying costs the usual penalties but never resets the counter, and progress persists across sessions and accrues offline.
Pay for the step. With the counter full, spend 250,000 × (L+1) gold and 2,500 × (L+1) Echoing Crystals. Both are consumed. Until you pay, the region simply sits at L with a full counter.

Purchasing follows the same rule as the dropdown: region map view, combat stopped.

Step	Frontier kills	Gold	Echoing Crystals
→ I	free after Theron	—	—
→ II	1,250	500,000	5,000
→ III	1,500	750,000	7,500
→ IV	1,750	1,000,000	10,000
→ V	2,000	1,250,000	12,500
→ VI	2,250	1,500,000	15,000
→ VII	2,500	1,750,000	17,500
→ VIII	2,750	2,000,000	20,000
→ IX	3,000	2,250,000	22,500
→ X	3,250	2,500,000	25,000
Full climb	20,250	13,500,000	135,000

Taking all five regions to X therefore costs about 101,000 quota kills, 67.5 M gold, and 675,000 Echoing Crystals. The fees deliberately outrun what the quota kills alone bring in, so expect to farm between purchases — and the crystal bill is why the Endless Delve stays useful long after its highscore stops moving.

Payoffs

Gold and XP

Both rewards grow with every step:

Gold scales linearly. The average roll is effectiveRank × 1.25, multiplied by the rarity (×2 rare, ×4 special) and spread ±20%.
XP: every applied level above I adds +10% kill XP on the region’s combat tiles (+0% at Resonance I, +90% at Resonance X), on top of Scholar and the Mead. An enemy’s own XP counts only up to 10 levels above you, so a higher tile alone does not pay more once it is that far up. See XP & Leveling.

Magic Find

Resonance-raised combat tiles grant Magic Find once their effective rank passes 100:

magicFind = min(+100%, +1% × (effectiveRank − 100))

That is 0 at or below rank 100 and caps at +100% at rank 200 — every region’s top tile at Resonance X. Since all regions share the ladder, they are equally good Magic Find farms at the same Resonance.

Dungeons and the Delve get no Resonance Magic Find regardless of their rank.

Material drops

Echo Shard and Echo Core drop chances are multiplied by the region’s applied level:

materialDropMultiplier = 1 + min(+200%, +20% × applied)

So Resonance V triples the shard/core rate (+100%) and Resonance X caps it at +200% — the main reason to push a region you intend to farm for crafting materials. Each drop is a stack of 1 up to the gear tier of the enemy’s level (level 1–20 → 1, 21–40 → 1–2, …, 81+ → 1–5), so every Resonance tile drops 1–5.

Keys

Special enemies on a cleared tile of a region with applied Resonance ≥ 1 can drop that region’s Key — 1% per applied level (1% at I, 10% at X), in every farm region from Resonance I on. See Echo Ascension for the full boss chain.

The region ladder

Region	Base ranks	At Resonance I	At Resonance X
Parched Grasslands	1–19	92–110	182–200
Cursed Swamp	20–39	91–110	181–200
Scorched Foothills	41–59	92–110	182–200
Shattered Mountains	61–80	91–110	181–200
Dark Citadel	82–100	92–110	182–200

The Dark Citadel is the finale region and drops no Key. Rank 200 — every region’s top tile at Resonance X — is the designed endgame wall, and the point where Resonance Magic Find maxes out.