Darth Calthius was the Dark Lord of the Sith from 30 ABY until his death in 86 ABY, as well the Sith Emperor from 40 ABY until his death. Widely considered the most powerful Sith Lord in history, he was responsible for the utter destruction of the New Jedi Order, the Skywalker family, and the Galactic Alliance, establishing the New Sith Order and New Sith Empire.