Him
The deal was simple. I got to experience Life on the small and finite level, including an ending. I was allowed to have senses and temptations and feel the notion of risk with dire consequences. All for the duration of one single carbon based lifespan.
In return, I allowed him access to the infinite knowledge that I am. Well, at least the amount that he was capable of handling as a carbon based lifeform. Further, I gave him the capacity to understand the true nature of forms and ideas and not only the echos of the truth which his kind normally are given.
Thus, the beginning of our deal was struck when I sent him off to be born so that I might understand the experience.