The great prison of Carceri is not a place one would wish to live in often, but this breed of aasimar have not only survived living as constant wardens; they have flourished. As the foremost level of security, chainwrights are often charged with capture and containment, and they have gotten very good at it over the aeons.
A huge number of Chainwright Aasimar can be found under the Eidal of Chains and living within Calvara, The Theocracy of Irons.