Umineko Tweak has released an updated patch of Rondo and the Witch of Reasoning which gives the game text boxes. Can be found here
Originally some sort of inner being in Eva Ushiromiya, she became a witch after Eva solved the riddle of the Epitaph. She was recognized as Beatrice's successor, and was extremely cruel. She often used her powers to kill and resurrect people multiple times (usually in brutal ways) before finishing them off. She is sometimes referred to in the text as "The Cruel Witch", and later on, "The Black Witch". She is the main antagonist in Banquet of the Golden Witch.