Damage math: increase versus amplify

If you have ever picked up a large percentage bonus and watched your damage barely move, the cause is almost always one of two things: it was applied to a value you never built up, or it landed in a pool already full of other percentages. Sephiria uses two different verbs for “more damage” and they behave nothing alike.

Increase and amplification are not the same word

An increase adds its value directly. Physical Damage +6 puts six points into the Physical Damage pool regardless of what else you are carrying.

An amplification raises the accumulated value by a percentage. Physical Damage Amplification +15% does not add fifteen of anything — it takes whatever your Physical Damage currently totals and raises it by fifteen percent. And critically: multiple amplifications are summed, not multiplied, pooling into one figure rather than compounding on each other.

Those two rules together explain nearly every disappointing percentage in the game.

Why a percentage can do nothing

First: a percentage of a small pool is small. Every run starts each of the four damage types at 20. If you have put nothing into Fire Damage, a Fire Damage Amplification of any size works on a base of twenty and the result is a rounding error. The three costumes granting an element amplification each hand you a matching starting item for exactly this reason.

The practical order is therefore flat first, percentage second. Early in a run a handful of flat elemental damage beats an amplification; later, with a large pool, the ranking flips. The same artifact can be the best or worst pick in one run depending on when you see it — see stats explained for which stats feed which pool.

Second: amplifications share one pool. Because they sum, the first amplification you take is worth more than the tenth — once you carry a lot of it, another card with the same number moves your final multiplier by much less. That is not a hidden soft cap; it is what addition does to a growing total.

Third: the bonus may not apply to what you are doing. Weapon Damage does not touch grimoire casts, Grimoire Damage does not touch weapon swings, and Special Attack Damage touches only special attacks. The item pages name the source each bonus attaches to.

What multiplies rather than sums

Not everything pools. Projectile grimoires are the clearest exception: the skill’s own damage scales off your matching damage stat, and then two separate percentage bonuses apply one after another instead of being added. That is why grimoire builds scale sharply once both halves are present — and it does not generalise to every skill.

Critical damage is also a multiplier rather than a pool member. Your Critical Damage rate is added on top of the hit rather than replacing it, so a rate of 100 makes a critical land for double. Execution doubles the rate’s contribution rather than the final multiplier: at a rate of 100 it produces a 3× hit, not a 4× one. Anything raising Critical Damage raises that multiplier, which is why Critical Chance and Critical Damage are worth almost nothing apart and a great deal together.

The order a hit is resolved in

The order matters more than any single formula, because it tells you what each stat competes with. A hit resolves roughly like this:

1. Checks that can stop the hit entirely — faction and validity, Protection Points, a counter or parry, dash invincibility, guarding.
2. Base damage multiplied by the final damage multiplier.
3. The attacker’s conditional modifiers — the “when the target is burning”, “while at full HP” effects.
4. Critical hit or Execution.
5. The defender’s damage-taken modifiers.
6. Elemental resistance. Positive resistance is capped at 99, and against a compound element only the single highest matching resistance applies rather than all of them.
7. Defense, on the curve below, with Ignore Defense resolved here.
8. True Damage added, Toughness subtracted, and a floor of 1 — no hit ever lands for zero.
9. Shields, including the MP shield.
10. Super Armor.
11. Clamped to the target’s remaining health.

Two things fall out of that list. True Damage arrives after Defense, so it is the one damage source armour cannot touch — but before Toughness and Super Armor, which can. And dash invincibility, guarding and Protection Points are not evasion; they are checked at the top, long before any dodge roll, so they cover a different moment rather than adding to the same defence.

Defense: a curve, not a percentage

Defense removes a share of each incoming hit on a logarithmic curve, not a linear one. The share removed is ln(Defense / 40 + 1) × 0.445 of the hit, and it runs all the way to a full hit removed.

Defense	Share of each hit removed
40	30.8%
80	48.9%
110	58.8%
200	79.7%
339	100%

339 Defense removes the whole hit, and there is nothing above that worth buying. The climb is brutally back-loaded: the first 40 points remove 30.8% of every hit, while the 139 points between 200 and 339 remove only 20 more. That is why piling armour on armour stops feeling like progress long before the number stops climbing.

Percentage points understate the late game, though — going from 58.8% to 79.7% removed halves the damage you actually take. And full reduction is not immunity: the floor of one damage per hit is applied after Defense, so even a completely absorbed hit lands for one.

The mirror case costs people runs: negative Defense is not neutral. Below zero the curve is abandoned and the reduction becomes Defense ÷ 100 of the hit, so −20 Defense means taking twenty percent more damage from everything, not simply losing your armour. It is easier to reach than it sounds: the Mole costume alone gives up 20 Defense, and Shock strips 20 more from whatever it lands on.

Evasion, honestly

Evasion converts into a chance to ignore a hit outright, on a logarithmic curve of its own. Unlike Defense, it finishes: the curve stops reading your Evasion at a displayed 100, and 100 Evasion is worth a 76.8% dodge chance. Everything above that is discarded before the chance is calculated, so Evasion is the one defensive stat you can genuinely max out — and the one where an extra point can be worth exactly nothing. A separate absolute Evasion is added straight onto the resulting percentage after the ceiling has been applied, so those sources are worth far more per point than they look.

Then comes the counter-play. Ignore Evasion scales your final dodge chance down by its own percentage. A boss modifier that ignores 50% of your Evasion halves it: a capped 76.8% becomes 38.4%, and no further Evasion tops it back up, because the input was clamped first. Evasion fails hardest against exactly the enemies you most want it against, which is the argument for pairing it with something that does not — see hard mode planning if you are choosing which modifiers to run.

What this guide will not tell you

Some pieces of the model are genuinely not stated by the game, and a plausible-looking formula is worse than an honest gap:

• Where each bonus category sits relative to the others. The order above is the sequence a hit passes through, not a set of coefficients you can multiply together into a damage number.
• Whether Ignore Defense cuts Defense before the curve is read, or trims the reduction after it. The two produce different results and the game does not distinguish them.
• Weapon coefficients. Weapons never show an attack number of their own — they are defined by their moves, costs and timings — and a multi-hit chain does not weight its hits evenly.
• Exact debuff coefficients. Every damage-over-time effect scales off the matching damage pool, but the percentage differs per source — status effects covers the shape of each one.

One last detail behind a lot of confused comparisons: the damage number that pops over an enemy is rounded, while the health actually removed is tracked more finely. Judge a build by how fast things die, not by single pop-ups — and if the numbers look right and the run still feels wrong, check what your costume changed; several rewrite this sequence rather than adding to it.