As the name would suggest, these catacombs are found in the Consecrated Snowfield. One of the more maligned dungeons in the game, these catacombs are full of Erdtree burial watchdogs, Cleanrot Knights, and the usual gargoyle imps. As if that wasn’t enough to worry about, there are also numerous frost traps to contend with — fortunately, the boss is a relatively easy encounter.
From the site of grace, head east up the first flight stairs, and then stop on the landing before heading up the next flight — there is a gargoyle imp on the wall ahead who will jump down and attack once you reach the next landing.
As long as you walk (instead of running) up the stairs, the imp’s attack will miss, and you can take it out. Continue up the next set of stairs, and wait at the top for the frost trap to finish spraying (if it doesn’t trigger, get a bit closer to the tunnel and then back off). Once the trap stops misting the tunnel — sprint in and take your first right into the alcove. Wait there for the trap to finish firing again, then leave the alcove and head due south, taking a left into the next alcove, where a gargoyle imp waits to ambush you — punish it for its audacity!
Optionally, you can wait for the trap to fire again, and then run into the room with the trap and disable it. This will lower it, and you can jump onto it and do a jumping attack (or attack it and then jump on) and ride the trap up to the platform above — naturally, there’s an imp up there who’ll attack you on your way up. However, all that’s on the platform is Rejuvenating Boluses, so you may not want to bother.
Either way, you’ll next want to head east through the tunnel where the audacious gargoyle imp ambushed you — in the next room, you’ll find the boss doors. Turn right to head south up the stairs, and once again wait at the top for the trap to finish spraying ice. Then sprint through the tunnel and make an immediate left. A burial watchdog will jump down, and there’s also a gargoyle imp on the right side of the room throwing knives, so quickly make your way to the corpse indicated below while sticking to the left side of the room. Grab the x4 Root Resin and then get to the far side of the trap and hide behind it.
From here, you can avoid the watchdog’s projectiles — your next destination is through the tunnel to the east. There are four imps in this next room, and they can quickly stack bleed on you. The best way to deal with them is to run into the room, grab the Grave Glovewort , and then run back out of the room without fighting them. In the room with the trap, run past the back of it and then into the nearby hallway on the western wall.
Don’t linger in the hallway or the imps will catch up with you — they’ll stop chasing you if you get into the next room, so continue through the hallway as it turns left. Go quickly into the next room, but watch out for the imp on the right waiting to ambush you. Then run up the stairs and kill the dagger-throwing imp, and head south into the next room. Here, another burial watchdog stands behind a corpse with the Imp Head (Elder) — there’s also a Grave Glovewort  on the back wall just to the right of the watchdog, and in the corner on your right just beyond the doorway is a corpse with x8 Human Bone Shard.
Once again, your best bet is to run in and grab the items, then run out of the room and down the stairs — grab the stuff from the corpse by the door on your way out rather than as you enter. Once you’re at the bottom of the stairs, turn around and go past the stairs to the dark area under the balcony. Turn left into the narrow tunnel and sneak into the next room, where a Cleanrot Knight patrols. Defeat her, grab the Grave Glovewort  in this room, and then go partway up the stairs that lead north. There’s a trap in the next room that fires at the top of the staircase, so you’ll have to run to the top of the staircase to trigger the trap, then roll back down out of the trap’s frost, and then sprint back up the staircase and roll to the left at the top of the stairs — this is because an imp will attack from the right.
If you’re lucky, the imp will die to the trap, otherwise, you’ll have to deal with it the old-fashioned way. Then hit the trap to lower it, and go grab the Grave Glovewort  from the northern end of the balcony. Next, head into the nearby tunnel that leads west. In the room at the end of the tunnel are two Cleanrot Knights and a Ghost Glovewort . These are tough foes to face, so your best bet is — you guessed it — grab the glovewort and then turn around, sprint back to the trap, and activate it.
Because the knights have ranged attacks, they won’t follow you out of the hallway, and they’ll die to the trap after a few bursts. Once they’re both dead, hit the trap again to lower it, and then roll onto it. Ride the trap up and then hop off to the south. Pull the lever that opens the boss door, pluck the Grave Glovewort , and grab the Golden Rune  from the corpse hanging off the balcony. Then roll back onto the trap, lowering it again, and jump down to the ground floor — watch out for the erdtree burial watchdog (if it’s still alive). Continue north-northeast into the hallway and down the stairs, and the boss doors will be open on your right in the next room.