There are 2 bands with the name Illumination:

1) Illumination from Norway (electronic)
2) Illumination from Belgium (Thrash metal)

1)
Illumination consists of the english/norwegian artists Nicholas Sillitoe and Per Martinsen (aka Mental Overdrive).
Both Sillitoe and Martinsen are known as true pioneers and innovators in Norwegian electronic music, club culture and alternative pop music production - paving the way for other electronica/pop artists like Røyksopp.
Illumination are also well known for their exquisite remixes under their "Chilluminati" monicker, notably the essential Café del Mar mixes of Mari Boine (Gula Gula), Bugge Wesseltoft (Existence). Both these remixes, as well as their own post-rave come-up, come-down anthem "Cookie Raver" have all been defining moments of the Café del Mar worldwide releases.
After releasing several 12" singles and e.p´s throughout the 1990´s, their eventual major label debut album came in 2000 "This Is Illumination" - with "The Chilluminati remixes" and follow up "The Poppy Rocks" in 2004.
Nicholas Sillitoe is currently occupied with many film and tv scores, and albums with norwegian singer/songwriter Anne Marie Almedal.
Per Martinsen is currently focusing on his electronica project Mental Overdrive, and productions with the band Frost.

2)
Illumination - Anno 2010
Illumination is a thrash metal band from Belgium. They have been playing for several years now and they were lucky to share the stage with bands like Asphyx, Hatesphere, Gama Bomb, Crucifier,... . also recorded a demo called 'Inside the warmachine' and the new demo called 'The Apocalyptic Era' is just released! Right now they are writing their first full album!

Stay tuned and check out their myspace:
http://www.myspace.com/illuminationthrash