Ash Lake is the most hidden area in the original Dark Souls — accessible only by passing through a false wall in the poisonous Great Hollow, which is itself accessed through a false wall in Blighttown. Neither false wall is indicated. The path requires the player to trust that the bottom of a toxic tree dungeon contains something worth finding.
What waits at the bottom is one of the oldest places in the world of Lordran: a white ash beach stretching beneath colossal archtrees whose trunks span the visible horizon. The area contains an Everlasting Dragon — a genuine Great Dragon, not a corrupted Drakeblood variant — standing motionless at the water’s edge.
The dragon can be attacked or spoken to. Speaking to it joins the Path of the Dragon covenant and grants a dragon eye. The item description and covenant lore establish that Ash Lake is a remnant of the Age of Ancients — the era before fire, before gods, before the game’s entire premise. You are standing in the world that existed before the world you have been playing in.
Almost nothing in Ash Lake is mechanically rewarded. The covenant items are niche, the enemies are sparse, the area is short. Its value is entirely in what it represents: a glimpse of a history the game’s framing device treats as almost mythological.

The level of craft hidden in the background of this game is genuinely moving. They made it for someone.
Didn’t realise how much was hidden under the surface. Makes me want to replay it with fresh eyes.