[Star wars] Lost fic: Obi-Wan Kenobi being Darth Vader and Emperor Anakin

I remember that it originally came from a collection of one-shots, but the author ended up developing it into several chapters. Obi-Wan had become Darth Vader, and Anakin was controlling the Emperor, so he controlled absolutely everything. And Luke was captured and taken away By Obi-Wan, he discovered the truth about his father and then tried to escape, but in the rebellion everyone believed he was a traitor, so they wanted to capture him.