Fugitive Criminal Key (Dark Souls 3)

At the end of one of the corridors there is a window behind the boxes, and a key from it. All the same, and so they wrote).

Angry Cat
Damn this window I opened a long time ago
Chet looks like I'm dull, but I'm at the very end where the sewer with rats and at the end two chests on the sides took the key

v-hlam The
second campaign is the old key to free Sigward (where the rats can talk, if it is not there then the quest is fucked up) and there is some other key to the rest of the chambers.
To all this you need to go from the bonfire of the forgotten capital. After the swamp with finished spiders there will be a structure and there is a passage to Siegward above the stairs, and if you go further, there will be another key.

Angry Cat
Thank you.
I found this cell where the rats are downstairs
But there is a window and not a door
Inside, except for some object, no one else
And shit from the opposite side
How can I get there?

v-hlam
I wrote that you need to go there from the fire of the forgotten capital. This is the tower to which there is a bridge guarded by a gargoyle.

Angry Cat
found everything
there, it was necessary to jump from the roof of the church in a swamp with toxin in the opening in the wall and then you get to him