Heading for the Gutter:

Meet the rat king, who will offer you to join his covenant.

Drop down the hole where the big skeleton is and loot a Pharros Lockstone (a key item used to activate certain mechanisms) from the corpse.

Use the coffins as platforms to descend; be careful as these drops are risky.

Drop to the pathway in the center and loot a Bleed stone (a material used for weapon reinforcement) from the corpse.

To reach the Disc Chime (a type of catalyst) on the broken ledge, you can do a sprint jump.

Alternatively, drop to the hanging bridge and loot the chest at the other end to get an Ash Knuckle Ring (an accessory that enhances certain stats).

Drop down, but be warned that exploding mummies will attack you. Kill them.

You can either head for the Gutter or use a Homeward bone (a consumable item that returns you to the last visited bonfire) to get the other item.

In the room with two tunnels, one leads to a corpse containing a Great Heal miracle (a type of spell), while the other leads to wooden scaffoldings that lead to the Gutter.

On the lower platforms of the scaffoldings, there's a Human Effigy (a consumable item that restores your Hollowing and increases your maximum HP).

Even lower, you'll find a corpse which possesses a Radiant Lifegem (a consumable item that restores HP over time).

Reach the bottom and loot a Token of Spite (a covenant item) from the chest.

Continue on to enter the Gutter.