Therianthropes? Lycanthropes? Animorphs? Homo-Zoological-Hybrid-Sapiens? Manimals? Take your pick.
Thunder and lightning is the sign of their shamans hunting and killing demons. Children's souls must be protected for their souls are not firmly in place yet and are easy for demons to take hold of. The shamans must hunt and destroy them and each break of thunder is another death of a demon hunting for souls.