Onheil was founded in the autumn of 1999. A few succesful demos lead them to the recording of their first official release, 'The Threat'. This very well recieved mini-cd was released in 2003 by the now deceased War Cry Productions. Unfortunatly, due to not being able to find a suitable drummer for recordings, Onheil has only been able to do live shows since then with several (session) drummers.

In the beginning of 2007 a new line-up was formed. This line-up now contains 2 lead vocalists and 3 guitarists, giving them more possibilities to perfect their own 'Black Metal Iron Maiden'-sound for which they are praised.