Board Thread:Speculation House/@comment-66.87.78.150-20151129211046/@comment-66.87.78.150-20151130021345

The way Winter explained summoning was that pretty much you can only summon things you have killed before, and not just anything that you've killed, they must be beings whose death caused you to change (or "grow" as Winter put it) as a person. There doesn't seem to be that much scientific process to it.