The item is used to improve the Hallowed Sword and unlock the second skill. We’ll tell you where to find it.
You need to get at least one Gland so that Ferris appears in the Fallgrim Tower. You will do it according to the plot. Then order Ferris to activate the fog by paying 1 Glimpse. Or, alternatively, do not give the Old Prisoner the Gland. Go to the big toad; follow it to the right and on the left hand look for a turn in the opposite direction. This path leads to a dead end camp of robbers, but this is where the stone toad stands. Open it will give you a Molten Spike.