The bizarre
mishmash of dimensions produced between the two worlds of
FF5.
Exdeath (Sorry, can't get myself to call him
Exodus) took this as his personal stronghold, and used the power of the
Void in there to grow stronger. A town,
Mirage, was sucked into the Cleft of Dimension when the worlds were separed: its inhabitants live in
stasis, outside normal time.
The only ways to enter the Cleft of Dimension are via a X-Zone spell, or through dimensional holes created by Exdeath.