The Achievement called ...It's Payback Time is part of Genshin Impact's Challenger: Series VII series and can be obtained by destroying the Shou no Kami's shield while he is delivering a powerful barrage of attacks. This is an Achievement that's easier done unintentionally, but if you're looking to complete the series ASAP, then I've broken down the easiest way you could manipulate the situation to get it. This took me multiple tries and a bit of RNG, so don't be alarmed when it takes you a while too.
How to destroy the Shou no Kami's shield while he is delivering a powerful barrage of attacks in Genshin Impact
To start this Achievement, you need to pay a visit to the Shouki no Kami Weekly Boss in Joururi Workshop, a Domain located in Chinhat Ravine. The boss battle consists of two phases: the first half pits you against the Shouki no Kami's upper body, while the second half pits you against his full body. The ...It's Payback Time Achievement can only be obtained in the second half of the battle.
The Shou no Kami has different attack combinations. For this Achievement, you need to wait for the exact moment he's about to deliver a powerful barrage of attacks, which looks exactly like the picture above. While he's in that state, you need to break his shield through any means—whether by using your character or the Neo Akasha Terminal. Doing so will reward you with the Challenger: Series VII Achievement "...It's Payback Time."
Related: How to get the Refusal of Thorns Achievement in Genshin Impact
Genshin Impact ...It's Payback Time Achievement full walkthrough
You need to time your movements perfectly to break the shield at the exact moment. For this, we recommend entering the Level 60 version of the Joururi Workshop. We also highly recommend bringing a Pyro and Hydro character. Upon starting the second half of the battle, an Energy Block will spawn nearby. Pick it up to charge the Neo Akasha Terminal.
Next, the boss will summon hats on the ground. Use a Pyro character to destroy Hydro hats and a Hydro character to destroy Pyro hats. You need to destroy at least two to obtain two Energy Blocks to fully charge the Neo Akasha Terminal. Use the Neo Akasha Terminal to break half of Shou no Kami's shield.
From here on out, there's a bit of RNG involved. There could either be two or three more Energy Blocks that will spawn before the Shou no Kami releases its barrage of attacks. You need to hope that three Energy Blocks spawn to fully charge the Neo Akasha Terminal—and don't forget to pick them up.
As long as your Neo Akasha Terminal is fully charged, you'll be able to deplete the boss' remaining shield using it. Otherwise, try again!
For more Challenger: Series VII Achievements, check out How to get the Like Hopscotch? Achievement in Genshin Impact here on Pro Game Guides.