The album features performances by vocalists Elize Ryd, Rob Rock, Michael Kiske, Russell Allen, Sharon den Adel and Tony Kakko, as well as the participation of guest musicians Alex Holzwarth on drums and both Jens Johansson and Derek Sherinian on keyboards.
[4] Tobias Sammet, German musician and mentor of Avantasia, another metal opera which had its 6th album released in March 2013, received the news of Timo Tolkki's own project with initial sarcasm, stating: "Wow, someone is extraordinarily creative here: the title, the guests, the timing... What a funny coincidence, isn't it?!
"[6] When asked about if he was aware that this project would be compared to Avantasia, Timo replied that "Nobody owns a franchise to 'metal operas' which is not really an operatic format because it doesn't have any real dialogue between the singers.
"[7] In October 2013 Timo launched a news website for the project in which he announced the sequel to The Land of New Hope, which was provisionally titled Avalon II.
[11][12] On 28 January Timo revealed title of the album (Angels of the Apocalypse) and the rest of the cast: Fabio Lione (Rhapsody of Fire, Angra), David DeFeis (Virgin Steele), Elize Ryd (Amaranthe) and Caterina Nix.