Hunt for the Shrine of Balance

[Sojiro]

Hi! I've been working hard to look for hints for how to reach that place without just spoiling myself. In the end I couldn't find anything usable, so I went ahead and made an account here. (closest I got to a hint was someone on this forum saying the solution was simple but disappointing, then someone else answering they found it clever instead)

I know there's obviously a 5th Shrine of Balance which is "hidden from sight" and that I should "follow in the footsteps of Kilhagan" to get there (or once I get there, maybe). From the placement of the other Shrines and the free room on the map, I'm pretty sure it's the river tunnels, somewhere between the Hub and the Cache (although it might be below Castle Nex). But I have not been able to find how to get there.

I've thoroughly searched the Lair of the Trickster, since it's right below my target area and only accessible once you need the 5th Shrine, but so far no luck. I have looked at every single wall for a hidden switch and ran into each one of them in case "entrance hidden from sight" means "invisible wall". Since Kilhagan's last action was casting "the most balanced of all spells", I've also cast the two perfectly balanced spells in every single square (Shield and Force Field). And yes, that means also inside the blade pit traps.

I've search the Hub and Cache just as thoroughly, as well as the first floor of Castle Nex. I've done the same thing, minus casting these two spells, everywhere in the Forgotten River map above.

Now I'm stumped. I went back and talked to every single statue and read every single sign (especially those about Kilhagan and the Balance/5th element) but I don't see any hint of where to go. That's where I gave up finding the answer for myself, for the first time since I've started playing The Legend of Grimrock, and decided to ask for help.

Am I completely off? Are some of my assumptions correct? Can you point me to the hints the game gives you that are actually supposed to help me find that entrance?

[Isaac]

The location is essentially relative.

SpoilerShow

SpoilerShow

The essence of the location is relative.

[Sojiro]

The location is relative?
...
Does that mean that I must put 1 power stone on the altar of each of the 4 basic shrines?

[Pompidom]

the shrine of balance is exactly the same principle like the other 4 shrines where you put 4 power gems on to create your orb.

SpoilerShow

The table can be found in the Trickster's lair

[Zo Kath Ra]

You already mentioned the first hint:

~ Legend of Kilhagan ~

On his way to ascension Kilhagan roamed
the island in search of the hidden shrine.
A year passed and then ten. After a very
long time did the old Kilhagan finally understand
the nature of his error. The gate was revealed
not by the most complex but the most balanced
spell of them all.

The LoG2 manual will help you figure out the spell...
Page 12 (Magic and Runes)

And there's another hint, from a stone philosopher in the Shrine of Water on Sleet Island:

Oh thee seeker of the hidden shrine.

Only by standing in the place with perfect elemental equilibrium shalt thou summon forth the gate to the hidden one.

[Sojiro]

Thanks, I wouldn't have found it without your help. I was expecting The Most Balanced spell to be, you know, a spell. I already knew that this wasn't a spell, since it hadn't done anything and hadn't been registered in my list. But trying it again, it just does nothing without fizzling out.

If you hadn't told me to look at the manual, I wouldn't have thought to use something that was not actually a spell.

After defeating the master of the Trickster's Lair, there's nothing left but to go through the gate in Castle Nex, right?

[Dr.Disaster]

Seem i'm a bit late with the hint about looking for a specific floor plate best spotted in broad daylight.

Aye, once the Master is defeated and you got his staff and key all what's left to do is enter the gate inside the castle and watch the final sequence ... and perhaps notice there.

[THOM]

...or first explore all areas that you have left out or that were too hard for you...