Blog · Derived

Block Efficiency or Crit RES: which Block line a tank should keep

3 October 2026 · 6 min read

Two rare gear lines give the same Block Rate. One adds Block Efficiency, the other Crit RES. Which one is worth more depends on how often you block the attacker, and the chart shows the break-even point for your numbers.

The two lines Fact

A Mythic or Divine piece rolls four additional stats. On this shield each roll has a 2.4% chance to be a two-stat line, one of nine pairs with equal odds, so about one shield in 94 carries a given line. The tier is a random pick of three. The season multiplies the line: ×1 while the piece has no Season Level or comes from an older rank, ×1.5 from Season Level 1, ×3 from Season Level 33. The Block Rate half is the same in both lines at every size.

One hit, as the engine rolls it Fact

The engine rolls block first. A blocked hit cannot crit. Only a hit that is not blocked rolls for a crit. \(D\) is the share of a full hit you take on average.

$$ D=(1-b)\,X+b\,Y $$ $$ X=1+c\,(m-1)\qquad Y=\frac{1-f}{v} $$ $$ b=B-\alpha\qquad c=0.05+\chi-r $$ $$ m=\max(1.3,\;1+\mu-r)\qquad v=\max(1.5,\;1+E-\alpha) $$

\(B\) is your Block Rate in combat, \(\alpha\) their Accuracy, \(\chi\) their Crit Rate, \(\mu\) their Crit DMG, \(r\) your Crit RES, \(E\) your Block Efficiency, and \(f\) the share of a blocked hit your flat Block Efficiency removes (Block Mastery, for example). \(b\) and \(c\) are chances, so they stay between 0 and 1.

Every character starts with 5% Crit Rate, 50% Crit DMG and 100% Block Efficiency. So an ordinary crit is 1.5× and an ordinary block halves the hit. Accuracy is subtracted twice, from your block chance and from your block divisor. Crit RES is subtracted twice too, from their crit chance and from their crit multiplier.

Where the line is Derived

Primes mark the value with the line. Crit RES only helps on the hits you do not block, Block Efficiency only on the hits you do. One falls as your block chance rises, the other grows, and they cross once:

$$ S_{\text{Crit RES}}=(1-b)\,\big(X-X'\big) $$ $$ S_{\text{Block Eff}}=b\,\big(Y-Y'\big) $$ $$ b^{*}=\frac{X-X'}{(X-X')+(Y-Y')} $$

When they crit every unblocked hit even with the line, Crit RES only lowers the multiplier, \(X-X'=r\), and the break-even has a closed form, with \(e\) and \(r\) the line’s two sizes:

$$ b^{*}=\frac{r}{r+\frac{1}{v}-\frac{1}{v+e}} $$

At the top tier that is 75% against no Accuracy and 63% at 50%, where the divisor reaches its floor. Above 50% the floor eats the Block Efficiency half, and the break-even climbs to 100% at 73%.

A buff that is up for part of the fight changes \(b\) turn by turn. Both savings are straight lines in \(b\), so use your average block chance over the hits you take. Put your numbers in, or start from a preset.

How much block you can have Fact

Your block chance is a subtraction, so your Block Rate and their Accuracy cancel point for point. A 15.36% Block Rate line on you and a 15.36% Accuracy line on them leave it where it was. What decides it is the total on each side, and that total depends on the season you are in, your level, your gear and what you have filled in. The off-hand’s secondary stat alone tops out at 26%, 194%, 383%, 523%, 493% in Seasons 1 to 5, at each season’s level before Season Levels. Every Season Level after that raises the Base it is divided by: in Season 2 the Base is 99,040 at level 130, 219,493 at 150 and 1,260,676 from 220 on.

The calculator starts at the season you pick with every source you can keep building at its cap: relics, sets, Fantomon, companions, enhancement and Season Level. Gear starts the way most gear looks: one special line per piece and no Block Rate or Accuracy on the off-hand. Change anything to match your account, switch to their side for the attacker, then send the totals to the panel above.

Changing the season starts again from that season’s defaults. Flat stats (the off-hand, the flat part of Charms) are turned into percent with the Base at your level, and their side uses the same level. The Base follows your level with Season Levels and stops growing at the end of its table (level 220 for Champion). Skill level is the level shown on the skill. It sets the flat part of Charms and Techniques, it follows your level when you change it, and the game caps it at your level. The off-hand uses the equipment page’s own formula for a Divine piece of that season. Each two-stat line is a 2.4% × 1/9 roll, so twenty of them is a ceiling, not a build. All Fantomon are listed because the client does not say which season releases each one. Crossover companions come from limited events and start at 0. Dora’s tree opens with Harpadia, and one Rock Brawler statue on an unnamed island map is not counted.

Block Efficiency comes from fewer places: 100% for everyone, Block Mastery +58.8% at rank 24, the gear line (23.04% each), and relics from Harpadia on. No relic set gives it. Their crit comes from Insightful Eye or Mana Surge (75% Crit Rate), Boiling Bloodlust (+70% for 4 turns), Explosive Spirit (up to 144% at 8 stacks) and Crit Mastery (+42% Crit DMG). Two of those put their crit chance past 100%, and from there Crit RES only cuts the multiplier.

At the cap both sides pass 100% many times over, so neither cap decides anything. The difference does, and the two things that move it most are the off-hand’s secondary stat and the in-combat skills. That off-hand is also where you pick Block Rate or Crit RES directly, which the single-stat slider in the panel compares.

What to do Opinion

1. Add up your Block Rate in combat: the Character screen, Block Awareness, Yearward Cloud if your Fantomon has it, and Luminous Shield for the turns it is up.
2. Subtract the Accuracy of the attacker you want to stop, their Charms and Techniques included. Put both, with their crit, into the panel above.
3. Against bosses, keep Block Rate + Block Efficiency. A boss has under 7% Accuracy and crits at most 22.5% of unblocked hits at 1.5×, and 22.5% Crit RES from the rest of your build ends its crits.
4. Against Energy Burst, Omnirune Sigil and anyone else who keeps you under the break-even, keep Block Rate + Crit RES.
5. Check again once your Crit RES passes their Crit Rate + 5%. From there their crits are gone, and a Crit RES line is only a Block Rate line.

Not in the formula Fact

Damage over time, hits sized by a share of HP and rebound damage never roll block or crit, so neither line touches them. Crit RES also makes on-crit effects fire less often, such as a Charm that heals or stacks on a crit. That leans toward Crit RES and is not in the numbers. Flat Crit DMG (the flat parts of Crit Mastery and of Omnirune’s Fire rune) is added on a crit, and Crit RES does not shrink it. In PvP a governor can scale all damage. The Block Efficiency half never moves it, because the governor floors its block term at 1.5 for anyone under 150% Block Efficiency. The Crit RES half moves it only if you have the lowest Crit RES in the battle. Whether a true-damage hit rolls block at all is decided on the server, and the client does not say.

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