Each Echo has a Cost of 1, 3, or 4 that fills a 12-point budget, two main stats fixed by that Cost, and up to five substats you unlock through tuning — not reroll.
An Echo is Wuthering Waves' equivalent of Genshin's artifacts, but it doesn't work the same way: every Echo has a Cost of 1, 3, or 4, and each Resonator only has a 12-point Cost budget to spend across up to five Echoes. Two main stats come baked in depending on that Cost, and up to five substats get unlocked afterward through tuning — you don't reroll a bad Echo, you tune the blank slots it already has and live with what comes up.
Echoes drop from ordinary overworld enemies, not from the instanced dungeons you'd expect. You defeat a monster in the open world and then absorb it directly — that's the source of the item itself. The Tacet Field domains you spend Waveplate on work differently: they hand out Echo EXP materials and tuning resources, not new Echoes. If you're short on a specific piece, the fix is farming the overworld enemies that drop it, not the matching Tacet Field.
Echo rarity lines up with the enemy type: common enemies drop 1-Cost Echoes, elite enemies drop 3-Cost, and the big Overlord/Calamity-tier bosses drop the 4-Cost pieces that carry the strongest kit.
There's also a Data Bank sitting behind all of this, and it's worth raising before you farm seriously. It levels up by absorbing new Echo types — variety, not volume — and its level widens the range a tuned substat can roll and improves how good a "wild" Echo can come out in the first place. Farming below roughly Data Bank level 15 tends to produce capped, low-value pieces you'll end up re-farming later, so it pays to chase a few new Echo types across the map early rather than grinding the same one you already have.
Every Resonator starts with a 10-point Cost budget, which goes up to 12 once you clear the Data Dock upgrades that come with early progression. Since Echoes only come in Cost 1, 3, or 4, the only way to fill 12 points without waste is one 4-Cost, two 3-Cost, and two 1-Cost Echoes — the 4-3-3-1-1 spread that shows up in essentially every build guide, because it's not a preference, it's the arithmetic.
| Cost | Echo tier | Role in the loadout |
|---|---|---|
| 4 | Overlord / Calamity | The centerpiece — see below, it also gives you an active skill |
| 3 | Elite | Two slots, carries elemental damage or Energy Regen options |
| 1 | Common | Two cheap slots, mostly there to round out the budget |
Every Echo has two main stats, and which ones it can roll depends entirely on its Cost — not on luck the way substats are.
| Cost | First main stat options | Second main stat |
|---|---|---|
| 1 | ATK%, DEF%, HP% | Flat HP |
| 3 | ATK%, DEF%, HP%, elemental DMG bonus, Energy Regen | Flat ATK |
| 4 | ATK%, DEF%, HP%, Crit Rate, Crit DMG, Healing Bonus | Flat ATK |
That's why the 4-Cost slot is where you hunt for Crit Rate or Crit DMG, and why 3-Cost is the only place to fish for an elemental damage bonus main stat.
Substats don't exist on an Echo until you tune it, and tuning reveals one at fixed level breakpoints — level 5, 10, 15, 20, and 25 — up to a maximum that scales with rarity: a 2-star Echo gets none, 3-star tops out at 3 (level 15), 4-star at 4 (level 20), and only a full 5-star Echo can reach all 5 substats at level 25. Only 3-star Echoes and up can be tuned at all.
The pool substats are drawn from is: ATK, DEF, HP, ATK%, DEF%, HP%, Crit Rate, Crit DMG, Energy Regen, and damage bonuses for Basic Attack, Heavy Attack, Resonance Skill, and Resonance Liberation — no type repeats twice on the same Echo. Tuning itself costs Tuners scaled to rarity (Medium for 3-star, Advanced for 4-star, Premium for 5-star; five of a lower tier combine into one of the next), and once a substat is revealed its type is locked in — you can level the Echo further and it'll still be that same substat, just at a wider value range. There's currently no way to swap a bad substat for a different one short of scrapping the Echo and farming a new copy, which is why community feedback keeps asking for a proper reroll tool.
The practical upshot: check the first substat right after it appears at level 5. If it's dead weight for the Resonator you're building — Energy Regen on a pure damage dealer, for instance — recycling the Echo on the spot beats sinking more materials into it.
You either run one Echo set across all five pieces to get its full 5-piece Sonata bonus, or split into two different 2-piece sets to stack two smaller bonuses. The 2-piece bonuses are small and unconditional — a flat elemental damage or ATK boost you get just for wearing the pair. The 5-piece bonuses are the ones worth building around: bigger payoffs that are usually conditional on something you do in a rotation, like triggering an elemental status, landing a Heavy Attack, or using your Resonance Liberation.
Whether a Resonator wants a 5-piece set or two 2-piece halves depends on their kit and their weapon — a character who can reliably trigger a 5-piece condition every rotation usually outperforms the safer 2+2 split.
The single 4-Cost slot does double duty: besides carrying your best shot at Crit main stats, it supplies the Resonator's Echo Skill — an active, summonable ability you trigger with its own button in combat. Picking a 4-Cost Echo is a two-part decision: does its skill actually help this Resonator's rotation, and does its main stat line up with what the build needs. A powerful main stat on an Echo whose skill does nothing for your character is still a worse pick than a slightly weaker roll with a skill you'll use every fight.
One more thing worth saying plainly: Kuro has changed Echo Cost caps and tuning behavior across major updates before, so treat the numbers above as accurate for the current patch rather than permanent — if a future update reshapes the budget or the tuning odds, this is the kind of system that gets touched again.