In Farron Keep, can be reached by turning right when coming down the Keep Ruins Bonfire ramp and searching for a ladder near a structure. It will have Rotten Slugs infront of it, as if they were guarding the ladder. If you went to the small housing of Rotten Slugs that contains an Undead Bone Shard, you're too far left from the ramp.
Gives the player the Legion Etiquette gesture
It is reminiscent of Sif from Dark Souls 1 in lore and connection to the Abyss