Complex sentence: He also finds out that 3 years ago, large numbers of goblins were taken from their caves to work at the plantation, in this incident, many, many goblins were killed, abused and starved to death.
Split into simpler sentences: He also finds out that 3 years ago, large numbers of goblins were taken from their caves to work at the plantation. In this incident, many goblins were killed, abused and starved to death.