Complex sentence: The Ancient One and Kaluu agree to cast a spell, eliminating sickness, disease and age from Kamar-Taj; shortly afterwards, the villagers, while under Kaluu's mind-control spell, crown Kaluu king of the village.
Split into simpler sentences: The Ancient One and Kaluu agreed to cast a spell, eliminating sickness, disease, and age from Kamar-Taj. Subsequently the villagers, under Kaluu's mind-control spell, crown him king of the village.