Verge Galaxy/the Crunch Cascade
The Kyln was maintained by a pan-galactic consortium of common interest parties, these parties included all seven of the primary pan-galactic law enforcement agencies and a consensus majority of secondary system local enforcement cells, who joined by subscription.
Points of Interest
The Kyln had a 99.999% inmate mortality rate, but the most interesting thing about the Kyln prison was the pilgrimage sites of questionable veracity due to the expanding universe surge proximity, known as the Crunch, which was also referred to as the Genesis Cascade by Thanos of Titan.
The primary functions of the Kyln was to serve as a series of power-generating units, providing energy to over 200 planetary systems. The secondary function of the Kyln is that it served as a death-penalty-exclusive, maximum security containment unit where the universe's most dangerous criminals were imprisoned.
Thanos #7, (2004)
Constructed at the time of the universe's Creation Event, the "Kyln Moons" were massive, interconnected spheres that existed at the Crunch cascade, the constantly expanding edge of the positive matter universe. The Kyln's architect remained unknown. Galactus used the Kyln to imprison the Proemial Gods, Aegis (Lady of All Sorrows) and Tenebrous (of the Darkness in Between). Galactus imprisoned his enemies within the Crèche, where state-of-the-art stasis confinement cocoons were powered by energies generated by the Crunch. Over the millennia, the Kyln had served as a prison for criminals and miscreants from across the universe too powerful to be held elsewhere.