Baatorian Earthen Binding

You create a Pentagram linking an unoccupied space you can see within range to a precise location on Baator, the first plane of Hell. The land within the Pentagram is filled with brimstone as a part of the ground of Hell is summoned within.  After focused my for 1 minute this space grows to the size of a Gargantuan creature. Once the spell is complete you are then able to use the Gate spell to travel to a location of hell of your choosing. 

Only those who are in service to you, or are permitted by you directly, can enter or leave this space. If a creature is in this space when the spell is cast, it is pushed from the space to a legal space just outside of the summoned ground. 

In order to travel to a plane of Hell you need permission from the Lord of that Plane of existence.  If you don't have permission from at least one Lord of Hell the spell fails and you are unable to summon any ground from Baator. 

Deities and other planar rulers can prevent portals created by this spell from opening in their presence or anywhere within their domains.

When you cast this spell, you can speak the name of a specific servant of yours that resides in Hell (a pseudonym, title, or nickname doesn’t work). If that creature is in a plane of Hell other than the one you are on, the portal opens next to the named creature and transports it to the nearest unoccupied space on your side of the portal. You gain no special power over the creature, and it is free to act as it normally would.

This spell was created by Azmodeus after the death of Torm as a way of traveling to and from Hell, only those who hold a title within a Devil Lord's domain can learn this spell, once taught it cannot be untaught, tainted, or tampered with. Any title is sufficient, but even having a title doesn't mean you gain access to the spell, it must be given to you by the Archduke of that plane.