Flameborn 
Secret Red Marble Door
Blocks
-
Crafted by Carpenter - You get
×1
Crafting
Ingredients
-
Metal Sheets
×5 -
Red Marble Fragment
×100 -
String
×10
From the same artisan
Carpenter · 401 recipes
Source: see “Secret Red Marble Door” on the Enshrouded Wiki (enshrouded.wiki.gg, CC BY-SA 4.0)