Emperor powers + very good PK skills + very good prep knowledge and willingness to keep on hand.
He had a great build for making you think you weren't that close to dying when, in fact, you were.
He'd start with daggers and imperial defense and work on reducing your stats while STSF charged up. Then he'd sigil, switch to imperial offense, throw down his daggers, and crushing blow to lag you. Or just pummel and rely on STSF to cutoff. Sometimes he'd also lead with sigil so that the time to switch from "defense mode" to "offense mode" was shorter.