I don't think Meredith said "he and Rood". He was referring to Rood. Kiel and Rood were the only survivors from the demon world. Then again, it should be Kiel, who is the survivor and Rood, the resurrected child.
Also, I feel kind of like a broken record if I have to keep repeating my own thoughts between Meredith and the big DK, so, I'm going to simply say Meredith is a pretty old human.