The lore before ESO was that he had achieved CHIM, he used it against Cyrus (imperial-library.info) to remove the Pankratosword technique, and Swordsinging from existence after Cyrus used them to kill Vivec so hard that Tiber Septim had to CHIM him back into existence. ESO has retconned it so he was only AWARE of CHIM.
Vivec's trial (imperial-library.info) was after the Oblivion Crisis. He was put on trial for the murder of Nerevar, and Vivec had Azura called in as a witness. When Azura showed up, Vivec immediately throat fucked her with Muatra and fucked off to his plane of Oblivion, The Provisional House.
The book, "The Infernal City" then covers the following events, of the Dunmer trying to stop the moon from falling.
(post is archived)