How to make Corvo a duke in high Chaos as Emily? (Dishonored 2)

Played as Emily. He killed everyone (except Stilton - he remained insane):
1) Hypatia
2) Jindosh
2) Briana Ashworth
3) Paolo and Byrne
4) Duke Luca, but did not touch his double
5) Delilah
Lucia Pastor is alive.
I thought since there was no one left in Karnak who could take the throne of the duke or form a coalition government, then after saving Corvo, he would come to power, but instead, as it was shown in the game, Karnak plunged into chaos, and Corvo stands near Emily's throne. What have I done wrong ? I will say right away that I did not hesitate to kill the guards, groaners, rangers and witches, and did not hide from them and joined the battle if they discovered me - in general, I killed a lot. The civilian population did not touch. In the statistics after completing the task, the number of "killed civilians" was always "0".
I will also add that even having kept Stilton's mind intact, preventing his participation in the ritual to summon Delilah, Karnaka still plunged into chaos, only in the final video Stilton was shown with a sword in his hand.