The doom of Schism fell the day
There came a queen to claim the seat
And rule with sword and spear and fear
The City Door'd to ev'ry Plane
In which our fathers held a line
'Gainst foes infernal and divine.
But evil greed yields evil deeds
And brother fought with brother, til
The streets of Sigil ran with blood
And stained the marbled city red.
The City now was ruled by Pain;
Betrayal split our race in twain.
But through the doors our fathers fled
To ev'ry world, to ev'ry place
Where crossings may be made they stood
To keep the faith and guard the gates.
And we their children stand the same:
We keep the watch, lest chaos reign.
Atop the Spire still it sits,
But Sigil now is lost to us:
A Cage that holds imprison'd souls
Enclosed in bars as sharp as knives.
And watching, perched on Tiefling bone
is Pain, the Lady on her throne.
-- Ji X'jit'hu, Misu Te X'je f.XXIII (trans. Konu Yeoholf)
The history of the Tiefling race as promoted by the great Tiefling scholar Pheseis Eternal has achieved the status of orthodoxy and is generally considered, by anyone bothering to consider the matter, as accepted historical fact. Doubtless, historical documents pertaining to the Asmodian Curse lend credence to the potency of the Tiefling bloodline, if not its source.
However, there exists a challenge to the claim of purely infernal origins found in the Misu Te X’je (roughly, “Poetic Forms”), the oral history preserved by Tiefling tribes such as the Zu Yexa Keso but long dismissed by the Arcanus Assembly as fiction. In the Misu Te X’je Tieflings are described as a divine race created of both celestial and infernal parentage. They were charged with guarding the Celestial Gates, portals that connect the infinite realms of the multiverse, to prevent any one power – celestial, infernal, abyssal, or anything else – from gaining footholds on worlds not their own. The forms describe a great city, Sigil, “the City of Doors,” in which every realm is connected to every other. Here, the Forms claim, is the true ancestral home of the Tieflings, who kept and guarded the city as neutral ground.
A clue as to how this incongruiety with the Pheseis Account might be resolved can be found in Form XXIII, Ji X’jit’hu (“The Schism”), in which a group of Tieflings is said to have betrayed the city to a figure known only as The Lady of Pain. A civil war ensued, and those Tieflings who stood against the insurrection were overwhelmed. They fled through the Gates, but refused to abandon their duty: these Tieflings continue to guard the Celestial Gates but from the other side, remaining hidden and forever cut off from each other and their home.
What is not clear is if Sigil is meant to be understood to be a literal place, or a metaphor for creation in all its unknowable complexity, or a wholly fictional construct designed to reassure a cursed, broken people of a primacy of purpose never given by history.