Allen/___ is a set of collaborative metal supergroup projects by Symphony X vocalist Russell Allen.

[1] The project started with Swedish guitarist Magnus Karlsson (Primal Fear, Starbreaker, Last Tribe) as producer, main instrumentalist and songwriter.

[2][3] Together with drummer Jaime Salazar, the quatuor released three albums: The Battle (2005), The Revenge (2007), and The Showdown (2010).

In 2013, Timo Tolkki (ex-Stratovarius) and Jami Huovinen replaced Karlsson and Salazar, leading to the album The Great Divide (2014).

I also noticed that there were several other releases coming out with similar style but with different singers, and so the whole thing started becoming a bit too fabricated to me.