Codex Portico

A weathered leather tome with the image of an archway embossed in its cover. Its contents are a mishmash of different languages and scripts, scrawled together into a nearly incomprehensible mass.

While you bear the Codex Portico, magic cannot transport you to another plane against your will.

The Codex Portico contains notes on the myriad places and creatures of the planes. If you spend an hour studying the codex, you can make an intelligence check to gain insight into a creature, entity, plane, or faction of your choice. Add 2 to this check for each language you speak. Depending on the results of your intelligence check, you will gain:

 10-19
 20+

The Codex Portico is also a spellbook that contains the following spells:

* Arms of hadar
* Dimension door
* Teleportation circle
* Blink
* Contact other plane
* Arcane gate
* Plane shift
* Etherealness
* Astral projection
* Gate

## House Portico

The text within the Codex describes the family history of house Portico, an ancient line of tieflings that have spread across the planes of existence. Porticos are recognizable by their eyes, which have irises like iridescent fire opals.

 As far as the Codex knows, the Portico family began in Sigil, city of doors. Sigil is a city that lies at the intersection of every plane of existence, a place so unstable and magical that it doesn't follow the traditional laws of physics. The entire city is contained within a massive torus that floats above the Spire in the Outlands, an interplanar expanse of non-Euclidean topography. Sigil cannot be entered or exited by normal magic or portals, but instead has transportation magic of its own. Sigil is called the City of Doors because it is full to the brim with portals, places where space bleeds from one area or plane to another. Most of these portals can be traversed using a key, some object or action that activates the portal and transports the user through. Sigil is sometimes called the Cage, because without the right portal key it is easy to become trapped in the city forever.

Descendants of the Portico bloodline are a sort of Skeleton Key. They have the unique power to pass unimpeded through every portal and doorway in Sigil, and by extension, the entire multiverse.

The origin and nature of this power aren't detailed in the Codex Portico, but it hints that it has something to do with the ruler of Sigil, an enigmatic figure known as the Lady of Pain.

Naturally, this ability has made members of house Portico the object of great persecution. The Codex recounts tales of fleeing from plane to plane, alliances and betrayals, favors and violence. Now, house Portico is nearly wiped out.

The last entries in the Codex are written in common by a woman named Carmine Portico. They contain her notes on the strange and alien sights of the outer planes, the politics and intrigue of Sigil, and the story of how she came to settle down on the prime material plane.

Despite Carmine's vast cosmic travels, she somehow fell in love with "a mundane oaf and booze peddler" named Darren Motley. They never officially married, but they had a son together. She named the boy Davian Portico, after his great grandfather. Carmine's entries cut off abruptly. The last passage has a nervous tone, as she describes a sensation of being watched.