The cast-off shell is located far, far to the east in Hallownest beyond a lengthy room and a fight with Hornet. Inside the cast-off shell, the player finds the King's Brand which allows access to The Abyss and unlocks various dialogue options with many characters.

Where is the Wyrm in hollow Knight?

Lore. Wyrm's shell Kingdom's Edge is the area where the Pale King arrived as a large Wyrm before the kingdom was founded. He shed his shell in the east part of Kingdom's Edge and transformed into his smaller form.

Where do you fight Hornet the second time?

Hollow Knight Hornet 2 Second fight against Hornet takes place in Kingdom's Edge. The fight is very similar to the first encounter you have.