Path of Idle farming: what each chapter actually drops
Most bonus drops in the campaign do not get better as you push chapters. Abyssal Scales, Resonance Crystal, Void Stars, Pious Heart and Unique Chests all roll at the same rate in chapter 20 as they do the first chapter that carries them. What does change is the item level band and the value of the souls you pick up.
That single fact settles the “should I farm here or push on” question for most resources: if you want a flat rate item, farm wherever your team is comfortable, because the rate is identical. If you want gear or hero experience, push.
How a drop is rolled
Every drop rule publishes a base outcome that reads as guaranteed rolls plus a chance for one more. A rule at 0.2% means one roll happens 0.2% of the time. A rule at 150% means one guaranteed roll plus a 50% chance of a second.
Each rule also has a minimum and a maximum, and the real result sits between them. Encounter type and where your team is positioned change the outcome, so the published numbers are the base before those modifiers, not the final chance. Every chapter page shows its own rules with these values attached.
What each chapter adds to the pool
| Drop | From chapter | Base chance per roll |
|---|---|---|
| Echo of the Boss | 1 | 0.20% to 0.30%, rising to 0.58% to 0.87% by chapter 20 |
| Unique Chest | 1 | 0.02% to 0.04%, unchanged in every chapter |
| Pious Heart | 1 | 0.20% to 0.30%, capped |
| Souls | 2 | starts at 1.00% to 1.50%, falls with chapter |
| Abyssal Scales or Gazing Eye | 3 | 0.12% to 0.18%, unchanged |
| Resonance Crystal | 5 | 0.10% to 0.15%, unchanged |
| Rune Pouches | 5 | 0.16% to 0.24%, unchanged |
| Void Stars | 12 | 0.10% to 0.15%, unchanged |
| Faith Skulls | 19 | 0.10% to 0.15% |
Echo of the Boss is the one that scales up, which is convenient because the boss repeat cost also scales up: chapter 1 asks for 3, chapter 20 asks for 22.
Abyssal Scales stay at 0.12% to 0.18% forever. If Explore entries feel scarce, that is the design, not your farming spot. The Explore guide covers what to do about it.
Rune pouches roll a quality when they drop, weighted 10000 Common, 8000 Fine, 6000 Rare, 4000 Legendary, 1000 Mythic. So roughly one pouch in twenty nine is Mythic, at any chapter.
Souls: the rate falls, the value climbs
Souls grant hero experience directly. There are five, worth 400, 2,000, 10,000, 50,000 and 200,000 XP. Later chapters drop them less often but drop far better ones, and the trade is heavily in favour of pushing forward.
| Chapter | Soul drop chance | Average soul value | Expected XP per roll |
|---|---|---|---|
| 2 | 1.00% to 1.50% | 400 | 4 to 6 |
| 5 | 0.70% to 1.05% | 1,111 | 8 to 12 |
| 10 | 0.36% to 0.54% | 5,556 | 20 to 30 |
| 15 | 0.18% to 0.27% | 27,778 | 50 to 75 |
| 20 | 0.11% to 0.17% | 116,667 | 128 to 198 |
Farming chapter 20 is worth around thirty times as much hero experience per roll as chapter 2, despite dropping souls a tenth as often. Which soul you get shifts gradually: chapters 13 to 15 mix Frenetic and Undying, chapters 18 to 20 mix Undying and Eternal.
This is the mechanism behind levelling a benched hero quickly. Souls apply to the current Godsworn, so a stack saved from late chapters brings a new recruit up fast.
Chest odds
Seven chest types exist. Each guarantees its own quality and can roll upward.
| Chest | Its own quality | Better outcomes |
|---|---|---|
| Common | 83.41% | Fine 15.01%, Rare 1.34%, Legendary 0.13%, Set 0.10%, Mythic 0.01% |
| Fine | 91.32% | Rare 7.31%, Legendary 0.73%, Set 0.55%, Mythic 0.09% |
| Rare | 92.17% | Legendary 4.61%, Set 2.30%, Mythic 0.92% |
| Legendary | 89.29% | Mythic 10.71% |
| Mythic, Set, Unique | 100% | none |
Two things fall out of this. A Rare Chest is more than twenty times as likely to produce a Set piece as a Common Chest, which matters when you are chasing a set bonus. And a Legendary Chest is the only realistic Mythic source outside a Mythic Chest itself, at better than one in ten.
Mythic outcomes are conditional: they cannot appear at all from chest levels 1 to 10. Chest level 11 corresponds to equipment level 50, so Mythic gear is locked behind that band no matter which chest you open.
Chest level sets the item level
A chest carries its own level, and that level fixes the equipment level range inside it.
| Chest level | Equipment levels | Mythic possible |
|---|---|---|
| 1 | 1 to 4 | no |
| 5 | 20 to 24 | no |
| 10 | 45 to 49 | no |
| 11 | 50 to 54 | yes |
| 15 | 70 to 74 | yes |
| 20 | 95 to 99 | yes |
Hoarding low level chests to open later does not help. The level is baked in when the chest drops. Open them, and use the Sanctum to merge low chests into higher ones when the level gap gets embarrassing; the market and Sanctum guide covers the merge prices.
Practical routes
Push the campaign while gear is the bottleneck, because the item level band is the only thing that moves it. Each chapter from 9 onward has 4 chest sites and 15 level sites, and the chest sites are 4 enemy groups instead of 8.
Farm the highest chapter you clear comfortably when hero experience is the bottleneck, because soul value dominates soul rate.
Farm anywhere for flat rate items. Abyssal Scales, Resonance Crystal, Void Stars, rune pouches and Unique Chests do not care where you are, so take the fastest clear you have.
The resource economy guide covers which resource actually gates you at each stage, which is usually a different question from where the drops are best.
Which level you farm changes the payout as well as the difficulty: an enemy dossier now carries the encounter level scaling table with its drop and experience rates, and the equipment filter shows what the game would throw away for you.