Delain have revealed that they will moving forward with a series of guest vocalists following the recent departure of singer Diana Leah. Among them are: Marko Hietala (ex-Nightwish), Sharon Den Adel (Within Temptation), Anneke Van Giersbergen (The Gathering), Fabienne Erni (Eluveitie), Patty Gurdy, Noa Gruman (Sabaton’s legendary orchestra), Paolo Ribaldini, Johanna Kurkela (Auri), and Ruud…