On Pocket Dimensions, Windows and Tallow

From the Archives of Toluz Zekhat, Osirian Chronicler:

     The early life of the Archwizard Zanzibar Felts is largely unknown.  His diction and linguistic peculiarities suggest a Taldoran extraction, or at least training in Taldoran schools.  He is known to have lived in Egorian and Absalom, though scholars such as Torian have suggested that he spent time in both Qadira and Katapesh under assumed names.  I have elsewhere published my doubts on this issue, which in my view is largely irrelevant given the clearly northern flavor of his later dimensional theorums --- Felts may have been familiar with Garundi schools of magic, but they have very little influence on his important works. The records of the Arcanimirium show that he lived and worked at that institution for more than four decades, producing some of his more famous written works.  Felts' expertise with pocket dimensions is nearly legendary --- his refinements to the rope trick spell have been nearly universally adopted in both human and elven magical schools, and mark a major move forward in stable temporary pocket dimensions.  Other notable inventions include Felts' technique for harvesting the bones of elementals, and the use of refined elemental essences to create dimensional membranes. It is known that in 4601 AR Felts left Absalom for a period of at least 30 years, much of which was reportedly spent on other planes of existence.  In his unpublished journals, Felts describes the effects of putting dimensional membranes inside one another, warping material planes into spirals and other shapes, and dilating time within pocket dimensions.

I imagine Felts' maps all looked something like this.

     Felts returned to Absalom in 4632, but had aged tremendously and was at least partially mad. Zanzibar Felts gave a frantic series of brilliant, rambling lectures at the Arcanimirium in the summer of 4632, the notes and transcripts of which have formed the largest and most famous of his academic works.  The Serpent and the Window: The Last Lectures of Zanzibar Felts is the definitive work on extra-dimensional spaces, the creation of demi-planes and theoretical space-time bubbles. During these lectures, Felts was known to for challenging his audience to give him complex theoretical questions.  He would then step sideways into warded pocket dimension in which time was severely dilated, returning instantly with answers, written out in long hand and exquisitely researched.  These demonstrations of dimensional time dilation made him quite famous, but have lead to the speculation that Felts had extended his life in unconventional ways.  Near the end of the summer of 4632, his lectures grew less and less focused, and he made extensive use of pocket dimensions, reportedly stepping sideways at dinner parties only to return seconds later, aged and bearded, mumbling incoherent spatial formulae.  He disappeared in the fall of 4632 and  other than some apocryphal notes attributed to him from the late 4700s, he has not heard from since.

Clearly something awesome
trapped in there.

     Though his theoretical contributions stand on their own, Zanzibar Felts is also known for his unique magical devices.  The Felts Confabulator is a large device which pierces multiple planes of existence simultaneously, distilling their essences into a unique (though unstable) pocket dimension.  This device, as well as Felts' working notes on dimensional melding, are held in the Arcanimirium in Absalom.  The Feltzian Bag of Holding is one of the few examples of multiple nested pocket dimensions incorporated into a physical item, and The Serpent's Window is a large mirror that creates what appear to be unique copies of material planes, allowing for the creation of divergent futures.  Among his most infamous creations are the Black Candles, powerful magical items thought to be constructed from Balrog tallow.  The Black Candles allow their user to create a stable, sealed pocket dimension that is only accessible while the candle is burning.  All known examples have been used as powerful magical traps, exiling dangerous beings or objects to extra-dimensional prisons.   The fate of those inside a pocket dimension whose corresponding candle has been entirely melted is unknown.

Zanzibar's bag of holding had bags of holding in it.