Complex sentence: One is called "Tangri han", that is "Tengri Khan", who is thought to be identical to the Persian Aspandiat, and for whom horses were sacrificed, and the other is called Kuar, whose victims are struck down by lightning.
Split into simpler sentences: One is called "Tangri han" (that is "Tengri Khan"), who is thought to be identical to the Persian Aspandiat, and for whom horses were sacrificed. The other is called Kuar, whose victims are struck down by lightning.