Christofer Johnsson started to play the bass at the age of 15 and changed to guitar a year later. He has no formal music education and has never taken any kind of music lessons.
On July 26, 1992, Johnsson's parents house was set on fire. Christofer was on tour and not home at the time of the incident. Only one inch of a backdoor was damaged before the fire was put out, but the event was blown up in media and caused many rumours in the metal scene.
Therion is the first metal band with fully live orchestra featured. It is also the band which originated, popularised and influenced the symphonic metal genre.
Secret of the Runes title is written in the Elder Futhark alphabet on the front cover and it is transliterated as: "sekret of þe runes".
Therion frequently uses visual symbols on its album covers. Most of them are based on magick, occult, and Dragon Rouge themes.

Hendecagram, the star of Qliphoth, an eleven-pointed star also called Star of Seth, is the most commonly-used symbol by the band. The star symbolises the night side of the Qabalah. The hendecagram is important to Christofer's magick and his lyrics, and has been admitted as a band symbol.There is also a connection between the eleven points of the star and the Dragon Rouge's Draconian initiation, since its 1 + 9 + 1 levels together constitute 11 steps. The symbol appears on all the album covers (not only front covers, also in back and/or inlay) since Symphony Masses: Ho Drakon Ho Megas (1993).
According to "Lords of Chaos" by Michael Moynihan and Didrik Søderlind, Varg Vikernes, attempted to burn down the house of Christopher Johnsson. After the unsuccessful attempt, Vikernes posted a letter on Johnsson's door threatening: ..."a lesson in fear. We are mentally deranged, our methods are death and torture, our victims die slowly, they must die slowly".
Cristofer Johnsson is a member of the magical order Dragon Rouge, and many song lyrics are written by this order's head and founder Thomas Karlsson. The phrase "Ho Drakon Ho Megas", for example, is part of Dragon Rouge's central ritual, the Dragon Ceremony.
The word Therion is Greek for "beast" and it refers to the beast of the Christian Book of Revelation. However, the band's name originates from the Celtic Frost album "To Mega Therion."