Thats because with infinite order (Arcane) and and Light, there was no Death, it took the insertion of chaos (Fel) and corruption (Void) to that for Death to emerge. Blood, itself, isnt a major magic source and is likely an offshoot of others.
Life magic is generally about the creation and preservation of itself, moving a soul around at your whim is indeed the opposite of what Life magic is about! Im enjoying our use of the exclamation mark, as well!