Depart from the Sites of Grace - Ranni's Rise  to Renna's Rise.   Get the Snow Witch suit in a treasure chest.

Take the Sending Gate to Ainsel River Main and get the Miniature Ranni.

Rest at site of grace.  Choose Talk to miniature Ranni.

Go out from the Sites of Grace - Nokstella Waterfall Basin, find and defeat the boss - Baleful Shadow.

Baleful Shadow - Elden Ring Raiders

Get the Discarded Palace Key after defeating enemies.