It can be found in the fog rift catacombs in a fairly hidden spot only accessed after jumping ontop of one of the crushing spikes and finding it on an altar.

note that the stone sheathed sword can be found on other altars fairly late into the game but the fog rift catacombs is the earliest part of the game where you can obtain it.


head to this appointed location on the map



you can reach this part of the map by taking a left detour from the Castle Front site of grace right before Castle Ensis and continuing the path forward. you'll find a valley formation with 2 wooden bridges. simply keep following the path straight and leftward until you find the entrance to the catacombs.

after entering, progress through the dungeon as you would normally by going through all the imps and crushing traps.

until you reach this part:

instead of jumping on top of the crushing trap, wait for it to rise and then jump down and into the hiding spot, after it rises again continue forward until you find an elevator, it will take you down further, from here clear the dungeon as usual.





you will then find this huge room with another crushing trap on top, your goal is to reach the end of the room by going into the various safety rooms on the left/right.









as one of the safety rooms has a hole that you can drop in, dont roll mindlessly into the safety rooms.


after reaching the end you can kill the caster mage and the imps next to him, if you face the direction of where you came from and wait for the trap to drop again, you'll notice that there is a pocket you can quickly jump into.




roll into it as soon as the trap drops. Jump into the platform and after you do that you should have a view outwards and be able to see the next room you need to enter.









this time just wait for the trap to rise again and you can walk ontop of it all the way to that room.





on an altar you will find the unremarkable;

The Stone-Sheathed sword can be transformed into 2 different legendary weapons. The sword you get is determined by which of the two altars you unsheathe the sword on. the location of these 2 altars will be shown.

IMPORTANT NOTE:
You can actually find the Stone-Sheathed Sword at either one of the altars of light and darkness, but wherever you pick up the stone sword will dictate where the altar that you can transform the sword will be, for example: if you pick up the stone sword at the altar inside of Unte, the altar required to transform it into the sword of darkness will now be the one in the fog rift catacombs, meaning you will have to go through the dungeon in order to transform the sword. its better to pick up the stone sword off the fog rift catacombs altar and transform it at either Unte or Rauh!

The description of the Stone-Sheathed Sword reads: A sword that none can pull from its scabbard of cracked stone. Relic of a lost civilization from a time long past, said to have served a ritual purpose at altars of light and darkness. this is the hint telling you that there's more to that sword than meets the eye.

this altar will provide, of course, the Sword of Darkness.

players will have to find the 'Ruins of Unte'. It can be found after progressing through the black keep and finding a ladder that leads to the Castle Watering Hole site of Grace. it is hidden quite well.


After entering the Black keep you will come across the Golden Hippopotamus fight, you need to kill this boss in order to progress, he's not that difficult but highly annoying. Play close to him and abuse his sides. while avoiding his bite/grab attack.


from here take the door to your left, it should be the only way to go anyways.










from here continue your path forwards and up the flight of stairs, there are quite a few of messmer's soldiers here, try to kill them as they can be a nuisance if kept alive. progress further until you find a room with 2 black knights in it.


after that, progress forwards again until you come across a place with boats on fire, should look like this.











from here continue forward and through all the Vulgar Militia tiny dudes but hug the left side, dont climb the stairs in the middle point, instead continue forward, you will find a ladder as such:











Take the ladder down, facing the ladder, go to the right side of it and you will be able to hug the wall while walking forward into a room obscured by a waterfall. Go through and you will find another ladder you can take, go down some more and you will find a room with a painting inside it that you can pick up, there is an illusory wall here. ill show you.




this wall will look different to you, its facing the painting though, simply roll into it or attack it to progress.



if you've reached this point, you should find a coffin, simply rest in it and you will wake up where the Castle Watering hole grace is, congrats! But we're not done yet.

you should be able to spot the ruins from here, all you have to do is go to where the entrance is to find a slumbering Furnace giant, you have to wake him up in order to enter the ruins, here's how:


after you do that, go to the left and climb the walls to a good spot that gives you access to the top of the Furnace Giant, all you have to do is throw the Furnace pot you crafted and he should come to life!!

you can either kill him or just go inside the ruins. after you do that you should find the Altar of Darkness on the rightside.

This is technically the hardest bit of the quest because reaching this point is such a long and lengthy process that it'd be much easier to show you a video i recorded of the route required. this is from the first miquella's cross site of grace (Rauh Ancient Ruins, East)







this is classic fromsoft, you wont die, all you have to do is walk across to that structure and you will be able to find the altar of light waiting for you.

IF THIS GUIDE WAS HELPFUL KINDLY LET ME KNOW

update: was aware of an issue where the youtube video in section 5 was not working, but it should be working now.