Darth Plagueis On The Old Sith And The Grand Plan (Star Wars: Darth Plagueis)
Taken from Chapter 5.
In this excerpt, Plagueis essentially recounts his precursors. While tampering with the midichlorians, he details the use of Sith Alchemy by the Ancient Sith. He also regarded the Banite Sith, on the Grand Plan.
Sources for some of the pictures:
Darth Bane attempts transfer essence on Darth Zannah: https://www.deviantart.com/vemiart/art/Battle-of-Wills-942644875
Darth Zannah: https://www.deviantart.com/automatan/art/Darth-Zannah-Order-of-the-Sith-Lords-Series-717027602
Darth Cognus: https://www.deviantart.com/automatan/art/Darth-Cognus-Order-of-the-Sith-Lords-Series-717380464
Darth Gravid: https://www.deviantart.com/automatan/art/Darth-Gravid-Order-of-the-Sith-Lords-Series-718946307
Darth Vectivus: https://www.deviantart.com/automatan/art/Darth-Vectivus-Order-of-the-Sith-Lords-Series-718471465