User blog comment:Piyush Banerjee/Shin DxD 2 discussion/@comment-36663391-20181203110438/@comment-32573280-20181203144218

IIRC Lint was recommened to Rias by the Vactican and I think by the Grigori as well other than that I think Lint joined because of her trying to atone for the crimes Freed made.