Ixaniad sector
Several hundred lightyears to coreward, beyond the troubled regions of Hazeroth and Adrantis, lies Ixaniad Sector (regularily misspelled 'Ixanid Sector'). The most common route between Scintilla and Ixaniad goes by way of Fenksworld in the Josian Reach, but other routes exists - including some that pass through the Hazeroth Abyss (for those brave enough it offers considerable savings in time) or the Markayn Marches (the latter is much used by the Department Munitorum to ship supplies to and from the Solomon world-depot).
Ixaniad is 'Old Country' - it's been part of the Imperium of Man for as long as anyone can remember - some of the world were United during the Great Crusade. There are also several world that have recorded histories well back into the Dark Age. It's also a place ruled by Old Blood and Old Money - mighty nobles houses (even the might House Krin of Calixian fame would rank as a middling power in Ixaniad) control all aspects of life on countless planets. The Adeptus Terra, while numerous, is relatively weak in the face of these Greate Houses. Ixaniad is rife with heresy - most frequently having to do with the corrupt vices of the upper class and forbidden technologies from humanity's dark past.
This is different from Calixis Sector, which is considered barely civilized, and has been part of the Imperium for only two short millennia. To Calixians the word 'Ixaniad' means old, corrupt, and overly gothic-baroque. Ixaniads hardly give any throught at all to Calixis, thinking of it not as a real sector, but a region of wild space.