The gate

How do I explain this? In my D&D campaign there is something buried deep within the earth called The Tesseract which is an incredibly vast dungeon for people to explore. There is no way that anyone could ever get bored as there are some really incredible things in there. The forgeborn sorceress Jen depicted here has for followers a version of Warforged from a part of the Tesseract. To move from section to section in the Tesseract (There is 600 layers to this dungeon) there is a system of magical gates.