User blog comment:IamJakuhoRaikoben/Chapter 433 & 434: Ikusatsunagi & Demolition Fist, Review./@comment-63.152.122.15-20150511182921/@comment-7418318-20150512073130

To me it sounded more like a one-term deal rather than an actual contract like the ones with Celestial Spirits.

Something along the lines of "I do x and when I need you you'll to y and then we go our seperate ways." though obviously with the almost complete lack of information I can't be sure.