As former collaborator NiDHOGG recently revealed the original demo tape via his Youtube page, composed by him in 1994:
Regarding the iLDjARN/Hate Forest split "Those Once Mighty Fallen"
"iLDjARN has confirmed to me that there's been a mix-up in regards to the source-material for the split. The songs are my original compositions in their entirety, though uncredited. Old tapes have been floating around . There is no quarrell between me and iLDjARN regarding this, it's a matter between him and OSMOSE.
The prelimenary synth-basses here represent parts of what was later to be recorded as guitar and bass. The songs are 6 of intentionally 12, in random order, with original lyrics drawn from and tracking Voluspå, the ancient norse tale of Ragnarok.
In the order they were recorded, with original titles, on my ca. '94 sketch-tape."
Additionally, NiDHOGG released another demo recording stemming from around the same time period. Similar in diverse ways to the more standard black metal material found on the split and the more feral material composed later; it is an intriguing glimpse back into the relevant years of black metal, even in a nascent form.
"2 channels from a 4 track recording of a demo I was working on about the same time as the previous upload. The guitar is placed aproximately in the right channel and the drumtrack in the left, so this is definitely not one for headphones. Channels 3 and 4, which on the tape makes up the b-side, can only be played the right way with a four-track recorder. As far as I can remember, session guitar (the one you hear) on this recording was by Thomas Haugen, iLDjARN played bass on the 3rd channel and my vocals were on the 4th (both inaudible on this upload). The recording was done in the basement at Akkerhaugen, were we did most of the live recordings. There was obviously need for overdubs, this was a first test recording more than anything, and the demo got shelfed as I focused on other things.
The picture on the screen, which was meant for the demo-cover, is from Mølen, a place on the coast were I've been many times from childhood. It consists of a stretch of beach littered with stones from the last ice-age, which was used as a burial site for powerful chieftans in the iron age."