After completing the main story, upon starting a New Game or a New Game+, you will receive Kuro's Charm when you pick up the Ornamental Letter at the start of the game. When you speak to Kuro in the tower and retrieve your sword, you have the option of giving it to him. Parting with the charm will give you a permanent 'difficulty' debuff, similar to ringing the Demon Bell. This debuff makes you receive chip damage when blocking attacks, effectively changing your play style. The Sculptor provides a dialogue option to remove this additional hardship; however, you cannot give the Charm back (and regain the difficulty debuff) until the next run.
