Keeper of Secrets is a mod for Darkest Dungeon, created by Bachvarov.
This mod introduces new class.
Once a noble monk, the keeper lost his mind when his monastery was raided and burned down. At the sight of this travesty he became so enraged he went on to attack everyone still present at the ruins of his old home. In his blind rage and madness he slaughtered all of his brethren as well as most of the raiders. Leaving his name and old life behind his only purpose now is taking the life of all those who would fight against justice... and in the end take his own life, for the sins he had commited..
Simply copy each of the folder into the DarkestDungeon game folder (usually here C:\Program Files (x86)\Steam\steamapps\common\DarkestDungeon\)
This should copy over and add some files to each of the folder. See below for instruction how to add the Effects and Localization.
It would also be a good idea to back up some files before hand.
Note: consult the effects_That_Need_To_Added.txt file for additional instructions or the game will crash!