How does the Corrosion mechanic work in the Genshin Impact Three Realms Gateway Offering Event

The Three Realms Gateway Offering is a 40-day event that runs from Feb. 17, 2022, to Mar. 30, 2022. It's set in Enkanomiya, the region hidden beneath Watatsumi Island. All players who have completed the following prerequisites are eligible to participate:

• Reach Adventure Rank 30 or above
• Complete the Archon Quest Chapter II: Act II - Stillness, the Sublimation of Shadow
• Complete the Enkanomiya World Quest Erebos' Secret

What is Corrosion?

Not to be mistaken for the Rifthounds' Corrosion debuff, the Three Realms Gateway's Corrosion effect is more akin to a meter that determines how much darkness is blanketing a particular area. This affects your gameplay: you can't easily explore areas with a Corrosion Intensity significantly higher than your Resistance level. Moreover, if the Corrosion Index is too high, you'll experience a significant deterioration in your Physical and Elemental Resistance, as well as overall Damage.

Related: How to complete the Three Realms Gateway Offering: Part I Event Quest in Genshin Impact

What is Corrosion Intensity?

Corrosion Intensity is the level of darkness in an area. You can find these values in the World Map, which specifies the Intensity of the locations that you may have trouble accessing. If you enter an area with a Corrosion Intensity that's a lot higher than your Resistance, the Bokuso Box's light won't be able to lift the darkness from enemies, objects, and more. Its light will also decrease at a moderate to fast pace, depending on how large the Corrosion discrepancy is.

What is Corrosion Resistance?

Corrosion Resistance signifies the level of Corrosion Intensity that the Bokuso Box can tolerate. It's possible to enter areas with a higher Intensity than your Resistance, but there's a high chance that the Box's light won't be strong enough to manage the darkness.

Increase your Resistance by leveling up the Bokuso Box. It starts out at six Resistance for level 1 and maxes out at 120 Resistance at level 15.

What is Corrosion Index?

The Corrosion Index can be found to the left of the mini-map. This value determines how much your battle performance is affected by the Corrosion Intensity in the area. The higher the Index, the larger the penalty to your Physical Resistance, Elemental Resistance, and Damage.

So, if you venture to a place with a much higher Corrosion Intensity than yours, you may find that you're taking more Damage and dealing less in return. Additionally, a very high Index will also increase the rate by which the light of the Bokuso Box decreases over time.

Check out our guide on Where to farm Light Realm Sigils in Genshin Impact — Three Realms Gateway Offering Event to quickly level up your Bokuso Box and build Corrosion Resistance.