"Blood of the covenant is thicker than water of the womb" meaning that relationships formed by choice are stronger than those formed by birth Now as a demon, Jisoo needs to learn how to survive, Jeonghan will have to stick with him every step of the way to help him adapt to new and possibly horrifying changes. (This is book 2 of Supernatural) Meaning of 'blood is thicker than water': family relationships and loyalties are the strongest and most important ones.