The Key of Heretic is one of the three Slab Keys used to unlock various cells and passages within the Slab in Hollow Knight Silksong. This guide will walk you through the exact location of the Key of Heretic, how to obtain it, so you don’t miss out on hidden rewards in Hollow Knight Silksong.
To obtain the Key of Heretic, begin at the bench where you first unlocked the Slab map. From this starting point, head to the right, drop down, and then proceed to the right into the lower section. Refer to the map below for the exact location.
Continue heading right until you reach a locked door. Use the Key of the Indolent to open this door and keep moving all the way to the right.
Now, you’ll need to carefully make your way upward, making use of double jumps, dashes, and harpoon swings while avoiding spike traps hidden on the walls.
At the top, head left and cross through an icy corridor. Once through and reach the end, drop down into a chamber where you’ll discover another bench.
From this bench, continue right and drop down deeper into the Slab. Follow the path until you reach a large arena filled with enemies.
Once you clear the battle, your reward will be the Key of Heretic. It is the third and final Slab Key needed to unlock hidden doors and shortcuts throughout the area.
