Songfacts®:

• "Into The Crypts of Rays" is the first track on Celtic Frost's landmark first album Morbid Tales. As such, it introduced the world to Celtic Frost, right when the New Wave of British Heavy Metal (often abbreviated NWOBHM) was gaining international attention.
• This song is about Gilles de Rais, who was the Marshall of France during the Hundred Years War, and companion-in-arms to Joan of Arc. Yes, that Joan of Arc. Gilles de Rais was also a famous serial murderer of children! He was tried and found guilty, and sentenced to burn at the stake. So Martin Ain read about him and made him the subject for a song. Why not?
• Celtic Frost was originally born out of the ashes of the group Hellhammer. Tom Warrior and Martin Ain, both doing vocals and guitars, were in Hellhammer when it disbanded, and began Celtic Frost along with session drummer Stephen Priestly. To this day, Priestly is a little chapped about being credited on the album as "session drummer," when by the time they got to recording he was playing a larger role. As Priestly says of the early stages of the band in his interview for Precious Metal: Decibel Presents the Stories Behind 25 Extreme Metal Masterpieces, "Tom went to London and came back with some records, some of that British heavy metal stuff, including the very first Def Leppard seven-inch and the very first Venom single - and said he wanted to do something like that, but even heavier. He wanted it to be the most brutal stuff people had ever heard. When he played me the first demos from Celtic Frost, I was blown away, so we made the first songs, like 'Into the Crypts of Rays,' and stuff like that. The amazing thing was that Martin and Tom had the vision for the first three records already in their minds."
• Also in Precious Metal, Tom Warrior mentions that the story of Gilles de Rais appealed to him when Ain showed it to him because of its "irony and sarcasm." And in the same paragraph, here's a peek into research work back in 1984: "Researching things like that back then was a huge undertaking, because it was pre-Internet. You really had to be a fanatic to get into all that stuff; you had to raid libraries and go to secondhand bookstores to find it. You couldn't go to Wikipedia or something like that." Now, did you young whippersnappers get all that?