Erebos’ Secret is one of the world quests tied to the lore and details of the Enkanomiya—a region hidden underneath Watatsumi Island. You will unlock this next quest after completing the From Dusk to Dawn in the Byakuyakoku quest series and bringing the Bloodbranch Coral to Tsuyuko.
You will start this quest by going to Enkanomiya in Evernight state and heading to The Serpent’s Heart. By the stairs of the tower ruin, you will find an afterimage or Sinshade named Eboshi, who will then tell you about three trials on three sub-areas of Enkanomiya.
The said trials are the Three Great Martial Trials: Yachimatahiko’s Trial, Yachimatahime’s, and Kunado’s. To get to these trial locations, you need to use the Emanant Skylights found in The Narrows, Evernight Temple, and The Serpent’s Head.
The water in the pool of each Emanant Skylight location will have Ghostfish Evernight, which will lift you to a Time Tunnel and bring you to the trial location.
However, a Primordial Bathysmal Vishap and two of its hatchlings will lurk around the area and attack you. Defeat these monsters first before proceeding with your task.
How to solve the Yachimatahiko’s Trial
This first trial is located in Yachimatahiko’s Locus, and to get there, you need to use the Emanant Skylight in The Narrows.
Once you get to the area, a Sinshade of the Jibashiri name Uda will be waiting for you at the entrance and introduce the trial. This challenge is the trial of wisdom wherein you need to solve puzzles to retrieve the Flames of the High Gate.
This puzzle involves a ruin with several closed areas where the Flames of the High Gate are locked in.
The easiest to get is the one that is sealed off by a magical barrier.
To remove such a barrier, go inside and up the stairs until you find the mechanism that switches Enkanomiya’s state. Interact with this and switch the region to go into Whitenight.
Return to the area with the Flame, and the magical barrier should be gone by now.
Now, head back to the entrance of this ruin where a Triangular Mechanism is situated. The mechanism can now interact since you have changed the region’s state to Whitenight.
Hit this one with any attack to open the cage in front of it and take note of the base of a broken mechanism inside.
Go back to the switch and change the region’s state to Evernight.
The broken mechanism inside the cage will now be in one piece again. Thus, you can interact with it to move the adjacent room/chamber wall.
Go to that chamber and take the second Flame of the High Gate.
The next thing to do is go up to where the region state switch is and glide towards the ruin chamber on the other side, where another Triangular Mechanism can be found.
Hitting this mechanism will move the wall on the opposite chamber and give you access to the Flame inside it.
The last Flame of the High Gate is situated way above the ruins.
To touch it, you need to climb up the cliff on the other side and glide down to where the Flame is.
After collecting all four Flames of the High Gate, ascend to the tower on the upper area and talk to Uda.
This will complete the trial, activate the tower, and unlock the “Extensive and Meticulous” achievement.
How to solve the Yachimatahime’s Trial
This second trial can be accessed by going to the Emanant Skylight in Evernight Temple.
When you arrive at the entrance of Yachimatahime’s Locus for the trial, another Jibashiri named Eki will be there to introduce the challenge and open the entryway for you. This challenge is the trial of sight where the battlefield is claimed to be ever-changing.
You will find many Specters that you have to defeat when you forward through the area. After doing so, go to the fountain you see in the area and interact with it by selecting “Observe.”
This will show the location of all four Flame of the High Tower in this trial.
The first one is on the remains of a broken structure just across the fountain.
The second Flame is in a pond with a couple of Hydro Specters that you need to defeat.
The third Flame is sitting right above a pillar-by path that leads to the tower.
And the last Flame is on the cliff right where the tower in this area is standing.
Again, after collecting all the four Flames of the High Tower, speak with Eki—the Sinshade who is assigned as the guard and guide of this trial.
The second trial is complete, and the second tower has been activated.
After completing this sub-quest, an achievement named “The Eel in Winter Sought” is also unlocked.
How to solve the Kunado’s Trial
The last trial is located in Kunado’s Locus, in the southern end of Enkanomiya. The way to get there is to go to the Emanant Skylight in The Serpent’s Heart, just below the Teleport Waypoint.
Once you get to the location, you will be greeted by Daimon—another shrine maiden Sinshades of the Jibashiri. She will explain that this final challenge is the trial of Valor, which is the power to defeat all your foes.
The Flames are on each of the four statues standing around the open area in front of the tower. But each statue is sealed off by a certain energy barrier, and each also has an unlit torch in front of it.
Switching from Evernight to Whitenight will not remove the barriers around the statues and will also turn two of the torches into Sunfire Phantasms.
The first thing you need to do is light up all torches using Pyro. However, ensure that your current team lineup can fight because several waves of monsters and enemies will appear when all torches are lit.
- The first wave of monsters are Thundercraven Rifthound Whelps. This means you need a healer and an Electro character to make this fight easier and for you to recover HP for the next waves of enemies.
- The second wave are three Abyss Mages of different elements. The said elements are Electro, Hydro, and Cryo, so include your character that can easily defeat these three.
- The third wave of monsters are two Bathysmal Vishap—one Primordial which uses Hydro and one Rimebiter which uses Cryo.
- The last enemy you need to defeat is an Abyss Herald: Wicked Torrents. This one uses Hydro so the best character to use against this one is a Cryo Vision user. Cryo attacks will freeze the Abyss Herald when it is in its Hydro-shielded state and prevent it from moving too much and attacking you.
After defeating all enemies and proving your courage, the barriers around the tall statues will be removed, and you can now release the Flames of the High Tower.
Now, talk to Daimon inside the tower so she can activate this.
After completing this sub-quest, the “Unmatched Throughout Tokoyo” achievement will be unlocked.
After completing all trials, return to Eboshi.
She will tell you you have been acknowledged as the hero of Watatsumi Island and thus given the privilege to ask any question about the history and mystery of this region.