It does say something about the perception of the passage of time when, upon seeing Hidden Fires Burn Hottest, my first thought wasn't "I haven't heard from these guys in a long time", but rather just delight at getting something new, only later piecing together how long it's been since I reviewed their previous album. Demo I and Demo II now very conveniently lie released twenty years ago, which does seem like a very long time ago, but it doesn't feel like nearly twice the time it took for Bosse-De-Nage to return with this album.
Long gap between releases aside, I am still in respectful awe at Bosse-De-Nage managing to seamlessly return after the absence and to still exist in the same formula for such a long time. Hidden Fires Burn Hottest doesn't feel like the result of a band that had to follow a long hiatus, and it feels like a very natural continuation from the hardcore infused post-black metal. What is instead a result of the long gap is that previously I remember Bosse-De-Nage being easier to lump in together with Deafheaven, a band they even released a split with. They've always been very different, but operating within the post-black metal wave of the time made the grouping more natural, but considering the evolution of both bands, that is a grouping that is increasingly hard to make, even if similarities are still present.
The biggest difference is that the post side in post-black metal (which is the more prominent as you do need to stretch the definition of black metal to consider Bosse-De-Nage a black metal band), while it does take from post-rock, it has nearly no shoegaze infusions, instead having the post-rock often feel more like its pre-crescendocore version, with more in common with math rock and post-hardcore, while still having just enough moments that keep it in line with the blackgaze sound. The vocals also having more of a rougher hardcore/sludge tone rather than a shriekier screamo/black metal one along with the tone being less ethereal and euphoric does make the sound of Hidden Fires Burn Hottest one less focused on that kind of contrast between harsh and mellow, but rather on a contrast of density.
The core of the sound is this post mish-mash I just described, one that is rougher in tone and more hardcore leaning, but Hidden Fires Burn Hottest is especially great at diversifying that by shifting around what goes into each track. Without going into track by track, I've had plenty of moments where very specific sounds by other bands like Slint, Godspeed You! Black Emperor, and strangely enough Fontaines D.C. (most likely through common influences). It isn't anything that fundamentally changes where the band left off with Further Still, but it's far from a rethread.
