The Three Realms Gateway Offering is a special event region in Genshin Impact that was temporarily added to give more details about the story of Enkanomiya, the Bathysmal Vishaps, and Reptilians—known as Vishap-humans and exist as the folklores of Watatsumi Island.
This unique region is a dark version of Enkanomiya and has three areas you need to explore. Each area has several collectible items for the event and includes some special and tricky puzzles that need to be solved.
In the middle part of the eastern of the second area, there is a puzzle where a Ruin Grader is locked inside a broken tower-like structure. The gate can only be opened by activating the switch in front of it. However, it is sealed and cannot be interacted with.
To remove the seal over the switch, you need to light up four Electro Totems that are also sealed. One totem is located on the upper chamber of the tower, two of these totems are just outside the tower, and the last one is above the cliff across the tower.
To lift the seal on each totem, you need to complete certain challenges.
For the Electro Totem located in the upper room of the tower, you need to complete the time trial challenge that is on one of the pillars across it.
This red eye-looking mechanism, which when activated, will start a shooting challenge. You need to hit five barrels that will explode once it gets hit. Destroying all five barrels within the time limit will remove the seal around the totem.
The two Electro Totems outside in the area around the tower will each have two Ruin Sentinels lurking around them. Defeating these mechanical monsters will remove the seals.
When fighting the Ruin Sentinels, look closely at their bodies. If they have dark smoke or aura coming out of them, use the Bokuso Box to clear that darkness and bring the monsters’ defense levels to be normal.
Again, the last and fourth Electro totem is located on the cliff across the tower. It is right next to a bit of the camp of Hilichurls. Defeat all the Hilichurls to remove the seal around this last totem and light it up using an electro attack.
Once all the Electro totems have been lit, the seal around the switch will be removed.
Go and activate the switch to open the tower gate.
The Ruin Grader will then stand up and attack you, so be prepared to fight.
This giant robot will also have that same dark aura as the Ruin Sentinels and other monsters in the region. Meaning you need to use the Bokuso Box to trounce this opponent.
Another thing to note when facing this Ruin Grader is that it will have a green circle where it is standing. This indicates that the Ruin Grade will heal itself over time. The challenge is to throw all your high damage attacks before the robot can heal itself.
After defeating the Ruin Grader, the treasure chests will be waiting for you as rewards for this challenge.
One of the treasures you will get here is a Light Realm Core that is needed to unlock one of the Bokuso Arts, which can aid you in exploring the special event region.