I was rereading Mistborn era one and in the end of The Hero of Ages, when Harmony fixes the world he leaves Spook a tome. Harmony said " Spook, it read. I tried to bring them back, but apparently fixing the bodies doesn't return the souls. I will get better at this with time, I expect." (pg. 723). So I was wondering does this mean that he can "re-alive" someone with only his power or does he have to use hemalurgy... (Kelsier?) or was Vin and Elend a one time thing?