MONO is a derivative of Monomania (German "Monomanie"), a term from the 19th century psychiatric disease theory, a form of partial insanity conceived as single pathological preoccupation in an otherwise sound mind.

Bass player Manuel Antoni joined in 2003, coinciding with the release of their self-published debut album Head Under Water.

During the production of their second album Temple Of The Torn in 2006, Miky Mono was replaced with Engler on vocals and Katha Mia on drums.

The album contains three new versions of songs from Head Under Water and a duet with Lisa Middelhauve of Xandria in the single "Teach Me to Love".

The song From the Ashes was performed live at the cruiserweight boxing match on 15 September 2012 between Yoan Pablo Hernández and Troy Ross in the Brose Arena in Bamberg.

Their seventh album, Nimmermehr, was released on 9 August 2013, reaching third place in the German Offizielle Top 100 charts in its first week.