Though lacking an official police force due to its clandestine nature, Abyss is held together these days by a strongly bonded criminal gang that operates with no name. They effectively enforce a code of conduct in Abyss and do so as they see fit. Though up for debate to an extent, their finances are likely earned from their heavy involvement in the sale of illegal items, most notably alcohol; they are furthermore involved in other criminal activities, but the extent to which this is the case is not well known. It can only be assumed from their strong hold on the massive Abyss that this extent is great, and that their power is, too.
Nevertheless, overall, this unnamed group has a positive reputation in Abyss. That is likely thanks to their usurping of the prior group in charge many years before the war, but the details of that event are not widely known, even in Abyss, of which many are members.
Abyss' top "authority" is an individual who goes by the moniker "Savage Mockingbird".