BootBoost

Every time the game starts it has to decrypt the .bhd files in the game directory, which takes a surprisingly long time. Fortunately if you decrypt them yourself and replace the files it will just load them directly, which is what this tool does.
I recommend using with the NoLogo Mod for maximum speed.
Requires .NET 4.7.2 - Windows 10 users should already have this.
Nexus Page

Installation

1. Drop BootBoost.exe into the game directory, usually "C:\Program Files (x86)\Steam\steamapps\common\DARK SOULS III\Game"
2. Run it.

Uninstallation

1. Restore the original files from the "BootBoost Backup" folder.

Credits

BouncyCastle

Costura.Fody by Simon Cropp, Cameron MacFarland