How do I reach Slumbering Sanctuary?

[Fetito Fazzito]

How do I reach Slumbering Sanctuary in order to obtain the spider rune?

[Sajonji]

start lvl > toxic sewers > old sewers > Insufferable Crypt > Slumbering Sanctuary

look here for future biome questions: https://deadcells.gamepedia.com/Biomes

[FlintX]

There is also another route too

[Sajonji]

Originally posted by FlintX:

There is also another route too

There are even more than one other route.
Black Bridge > Sanctuary needs Spider Rune. Therefore not viable if OP still needs spider rune.
Ramparts > Insufferable Crypt > Slumbering Sanctuary needs 3BC. Highly unlikely to have 3BC but no spider rune, therefore also not viable.
At the point where OP highly likely currently is, my first way is the only correct way to go.

[FlintX]

you don't say

[Fetito Fazzito]

So I need to start a new run a a higher difficulty in order to obtain the rune?

[Gem of Temporarity]

Originally posted by Fetito Fazzito:

So I need to start a new run a a higher difficulty in order to obtain the rune?

New run? Yes.
Higher difficulty? No.