Nah they didn’t prep anything. It wasn’t in the core gameplay of any forge. Hell I have about 20 clears on each forge and had no real clue about any of the “caveman drawings” till izanami. It was a side feature then and is now made a core component, with little to no explanation in any lore or story component about what the hell any of this is. It’s like we’re playing an FPS of X-Files. 😂