Diluc was the very first 5-star character I
pulled in Genshin Impact. At the time, I had a basic understanding of Reactions and I knew that
Melt could amplify the damage of Pyro attacks. When I read about Chongyun’s Skill and how
it could infuse my Normal Attacks with Cryo, I really wanted to get a copy of him. I had an
idea for a combo where I infuse Diluc’s Normal Attacks with Cryo using Chongyun’s Skill, and then
use a Normal Attack before each cast of his Skill so I could trigger a Melt reaction on all of them.
In my head, this seemed like a really strong combo that could amplify all 3 casts of Diluc’s Skill.
I finally pulled Chongyun a couple months later and was really excited to
finally try out this combo. To my surprise and disappointment, I
found that it didn’t exactly work as I had planned. The first Normal Attack and
Skill cast did trigger Melt as expected, but my second Normal Attack wasn’t applying any
Cryo on the enemy, despite dealing Cryo damage. I thought maybe I was misunderstanding the
mechanics behind Chongyun’s Skill, or that I was missing something about how Reactions
worked. I didn’t know it at the time, but it turns out that that was my first interaction
with a mechanic that we now understand as ICD. ICD stands for Internal Cooldown. It’s a
cooldown that’s not displayed anywhere, but determines how often an attack can apply
an Element or trigger an Elemental Reaction. For most attacks, this cooldown is 2.5 seconds.
This means after an attack applies an Element, we have to wait 2.5s seconds before
it can apply the Element again. If we go back to our example with Diluc, his
first Normal Attack is infused with Cryo and it applies Cryo on the enemy as expected. This
starts our 2.5-second cooldown. This means his Normal Attacks can’t apply Cryo on the enemy
again until 2.5 seconds have passed. We can see here that his 2nd Normal Attack doesn’t apply Cryo
on the enemy, because that cooldown isn’t up yet. Here’s a different example, where I’m waiting
for a couple seconds in between my Normal Attacks. Since the time in between each of
my Normal Attacks is more than 2.5 seconds, every hit does apply Cryo and I’m
able to Melt all 3 casts of my Skill. Even if you’re not interested in the details, you
can just think of ICD as something that limits the Reaction rate in this game. It’s basically
a balancing mechanism that prevents you from triggering Reactions too quickly.
When we think of ICD in this way, something that we might be more interested in is
whether there’s a way to work around it. If we somehow find a way to bypass this limitation,
we could apply our Elements more quickly, trigger reactions more frequently, and overall
deal more damage. And as it turns out, there are a few ways to work around it. For one, the ICD of different types of attacks are
tracked independently of each other. That means my Normal Attack has an ICD that’s tracked separately
from the ICD of my Skill, and both of those are tracked separately from the ICD of my Burst.
Yanfei is going to help us demonstrate this. We’re using a Hypostasis as our enemy, because
it has a permanent Elemental aura. This makes it easy to tell when we’re applying our Element
- every time we trigger an Overloaded reaction, it means we successfully applied Pyro. If we ever
deal Pyro damage but we don’t see an Overloaded reaction, that means we’re restricted by our ICD.
First, we have a simple example where Yanfei is just using her Normal Attacks repeatedly.
The 1st one does apply Pyro and triggers an Overloaded reaction as expected. But
the 2nd and 3rd attacks do not apply Pyro, despite dealing Pyro damage, because we
are still under that 2.5-second cooldown. Now, let’s look at a second example where
Yanfei is rotating through her abilities instead of just using Normal Attacks. What
we see here is that her Burst triggers an Overloaded reaction, and then her Skill
triggers another Overloaded reaction, and her Normal Attack also
triggers an Overloaded reaction. Even though all 3 attacks
took place within 2.5 seconds, because we’re using different types of attacks,
we can trigger a Reaction with all 3 of them. Knowing this encourages us to rotate through our
Skills and Bursts to maximize our Reaction rate, as opposed to using the same
attack over and over again. The second mechanic that can bypass the internal
cooldown is something that’s often referred to as the “3-hit rule”: if an attack has not
applied its Element for 2 consecutive hits, the next hit - that is, the 3rd hit - will apply
its Element, even if 2.5 seconds have not passed. To see this more clearly, let’s
replace Yanfei with someone who can attack a little faster, such as Hu Tao.
Our first Normal Attack applies Pyro and triggers an Overloaded reaction, as expected.
From this point, we would normally have to wait 2.5 seconds before our Normal Attack can
apply Pyro again. However, our 4th attack does apply Pyro and triggers another Overloaded
reaction, even though 2.5 seconds haven’t passed. This is thanks to the 3-hit rule. Since we
last applied Pyro on the 1st hit, we can apply Pyro again 3 hits later, on the 4th hit.
What’s more is that even though the 3-hit rule bypasses the ICD, it doesn’t reset the
original 2.5-second cooldown. This means that my 5th attack, which happens 2.9 seconds after
my 1st attack (greater than 2.5 seconds), gets to apply Pyro again and Overloaded one more time.
This is another mechanic that allows us to work around our ICDs, but instead of rewarding
combos that use different types of attacks, it instead encourages us to just
attack really, really quickly. Abilities that can hit multiple times
in quick succession or characters with really high attack speed, such as Ayato or
Yoimiya, benefit from this mechanic the most. This mechanic is one of the main reasons
why Xingqiu is such a strong Hydro applier. Xingqiu’s Burst enhances our Normal
Attacks to deal additional Hydro damage, but the key characteristic is that the Hydro
damage comes in waves of multiple hits at a time. This means that his Burst accumulates
hits very quickly and allows him to trigger the 3-hit rule much more frequently
than most other characters can. As a result, almost every Normal Attack that’s enhanced with
Xingqiu’s Burst will apply Hydro on the enemy. By the same logic, Yelan is also an
excellent Hydro applier. Her Burst conveniently comes in waves of 3 hits at
a time, so regardless of the ICD timer, that means every wave will trigger
the 3-hit rule and apply Hydro. The third and final way to bypass
ICDs is simply to use attacks that have reduced ICDs or don’t have an ICD.
In general, abilities that have higher cooldowns or can only hit every once in
a while, typically don’t have an ICD. But this is kind of balanced by the fact that
you can’t use them frequently anyway. (Most) Catalyst and Bow Charged Attacks also fall under
this category. But again, Catalyst Charged Attacks cost a lot of Stamina, and Fully Charged Aimed
Shots have a relatively long wind-up. So even though they’re not restricted by ICD, they already
have a kind of “rate-limiter” built into them. What’s a lot more interesting are abilities that
do hit frequently, but also have a reduced ICD. Venti’s Burst has an ICD of 1 second, allowing
him to trigger Swirls and a number of other reactions much more frequently in
the span of his 8-second Burst. Polearm Charged Attacks have an ICD
of 0.5 seconds. This relatively low cooldown is what allows Hu Tao’s Charged
Attacks to trigger Vaporize on every hit and make her the dominant carry that she is.
Kokomi’s Skill is another example, that ticks pretty frequently and can maintain 100% uptime
(with the help of her Burst), yet has no ICD. And finally, we have Xiangling’s Burst, which
is probably the most well-known example in this category. At C4, her Burst deals at
least 10 hits of Pyro damage in just 14 seconds. And with no ICD, every one of those
hits can apply Pyro and trigger a Reaction. These are the types of attacks that kind
of break the system. They get to hit frequently and they’re not restricted by ICD.
And it’s no coincidence that these characters are members of some of the strongest teams in
the current meta. These teams are strong exactly because they’re composed of characters that can
bypass the limitations imposed by the ICD system. Xingqiu and Xiangling make up the Reaction
core of the National team. As we saw earlier, Xingqiu is able to work around the limits of
ICD because his Burst takes advantage of the 3-hit rule very effectively. Xiangling’s Burst
simply doesn’t have an ICD. It’s only when you put these two together that you get the perfect
formula that enables Xiangling to trigger Vaporize on most or all of the ticks on her Burst.
The Melt Rosaria team that I love so much hinges on the fact that neither Rosaria’s Burst
nor Xiangling’s Burst has an ICD, allowing Rosaria to trigger Melt on nearly all of her hits.
As I mentioned before, Hu Tao teams take advantage of the short ICD on her Polearm
Charged Attacks, and also leverage Hydro appliers like Xingqiu and Yelan, who we already
know utilize the 3-hit rule to bypass ICDs. The Nahida Hyperbloom or Burgeon teams that have
recently risen to prominence depend on the shorter ICD of Nahida’s Tri-Karma procs. Combine this with
Kokomi, whose Skill doesn’t have an ICD, and you get a combination that allows you to trigger Bloom
much more frequently than typical Dendro teams. At the center of all of the strongest
Reaction-based teams, we can usually find at least 2 core characters who can work around - or even
completely ignore - the usual limitations imposed by the ICD system. This allows these teams to kind
of cheat their way into triggering more Reactions than most other teams are allowed to do.
Of course, there are other major contributing factors to why these teams are so strong, and why
others don’t work quite as well. Mechanics like snapshotting, Elemental gauge consumption,
damage uptime, and Energy constraints are all factors that come into play when
we look at what makes a team work. But ICD is certainly one of those factors, and,
in my opinion, one of the most important ones. This video that started with a simple Diluc
demo very quickly went down the rabbit hole of a pretty complicated concept that the
game doesn’t teach you about, but is very much relevant in its gameplay. As complicated
as it is, I hope this helped sort of demystify this somewhat obscure mechanic that is ICD.
Hopefully you have a better understanding of why some characters are so highly valued, and why some
team comps are put together the way they are. No matter what you took away from this video,
as always, thank you so much for watching.
