Steel Soul Mode

No Shade. No Reviving. Death is Permanent. The Ultimate Challenge.

Steel Soul Mode is a game mode in Hollow Knight that is unlocked after finishing the game for the first time.

In Steel Soul Mode, there are four main changes to gameplay, compared to Classic Mode:

The Knight does not respawn upon death. Once the Knight dies, the game ends and the save file is reset. Note: dying to a Dream Boss, or in Godhome, does NOT count as an actual death. However, dying in the White Palace or to the Radiance DOES result in a Game Over.
Unique animation upon dying.
Confessor Jiji is replaced by Steel Soul Jinn, who trades Rancid Eggs for Geo.
Tuk has been killed by the Infection, and does not sell Rancid Eggs. Found next to her corpse is a Rancid Egg.

As death is permanent, this means that the Fragile Charms sold by Leg Eater become significantly more useful, as their main penalty (breaking upon death) is nullified.

Trying to enter a failed Steel Soul run results in asking if the player would like to clear the save slot. The save slot also says the word "DEFEATED" instead of the location the game was last saved in.

In addition to two achievements, finishing the game in Steel Soul Mode unlocks a new Menu Style.