In Dark Souls II: Scholar of the First Sin there are three DLC locations which open the doors only if you find specific keys related to the DLC’s.
There are three keys in three different chapters of the latest Souls game, Scholar of the First Sin. If you cannot find the keys on your own, relax and go through this guide on how to find the LDC keys for Dark Souls II: Scholar of the First Sin.
It is a little difficult to find the first key or the Dragon Talon, it can be found under Majula in a old room which is full of treasure chests. You need to start with a mysterious doorway and go down to the second bonfire from the ledges from the Black Gulch. You will reach a cave containing two giants, when you kill these giants you will get
the Antiquated Key (corrected: The Forgotten Key) to open the door below Majula. You will find the Talon at the corpse when you enter the doorway.
Heavy Iron Key
Look for the Heavy Iron Key in the fire salamander pit under the Forest of Fallen Giants. Use the Antiquated Key which you found earlier or go down from the bonfire along with the Silvercat Ring. You will have to go deep within the cave to find this key near a corpse. When you reach a fire salamander you will get the Rebel’s Greatshield from the same corpse where you got the key.
The Frozen Flower
Near Drangleic Castle’s first bonfire you will find a corpse near the door that you will pass. Finding this key will be the most easiest of all the three DLC keys in Dark Souls II: Scholar of the First Sin.