Literal metals are always cooler when they come from space. A blade forged from meteoric iron is effectively the same as one made from iron you can find on Earth, but don’t tell me you wouldn’t want the space knife way more. Likewise, metal music always sounds cooler when it feels like it’s from another world. Enter ZU, the Italian jazz metal trio comprised of guitarist/bassist Massimo Pupillo, saxophonist/keyboardist Luca Mai, and drummer Paolo Mangardi. ZU forged their latest record, Ferrum Sidereum, Latin for “iron of (or from) the stars,” to sonically approach something otherworldly, drawing from the historical spiritual significance of meteoric iron as inspiration for their music. And forge ZU did, because Ferrum Sidereum is an 80-minute double album of progressive, industrial, punk-infused, and fully instrumental jazz metal. But is Ferrum Sidereum a gift from the stars, or should you look for your metal closer to home?
Ferrum Sidereum is a record that revels in texture and rhythm more so than melody. Like ObZen-era Meshuggah, ZU play melodically bare but rhythmically exquisite riffs, with their prog and metal elements manifesting into bouncy, syncopated djent jabs prominent on tracks like “Golgotha” and “Kether.” Guitars are low (“Ferrum Sidereum”), bass is plucked with abandon (“Charagma”), and drums roll with jazz-practiced precision and metal aggression (“La Donna Vestita Di Sole”). Industrial elements and saxophone conspire to either inject a sense of progression to simple riffs (“Hymn of the Pearl”) or, more often than not, tear your ears a new one with punkish, dissonant whines and whistles (“Fuoco Saturnio”). ZU bounce between these loud, crunched moments with Tool-like passages of meditative, methodical calm and repetition with a hodgepodge of percussive additions to fill out space (“Pleroma”). You likely won’t be able to hum anything off Ferrum Sidereum by the end, but it’s undeniable that ZU are very particular about sounding a very particular way.
ZU have the chops to carry the load of a double album, but Ferrum Sidereum unfortunately doesn’t have the substance to fill one. To achieve a sense of spiritual ritualism, ZU obviously had to rely on repetition within songs, but it quickly just gets excessive and bland. Differences between songs—like “AI Hive Mind” and its distinct, mathcore level of scronk in its guitar tone and saxophone or “Golgotha” and its use of ghostly choir to build unnerving atmospheres—get lost in the flood of crushed djenting that better defines Ferrum Sidereum. ZU stick to such a strict palette that following along to the album as a whole becomes tedious, and the lack of melodic leads or even just a singer make Ferrum Sidereum easy to drift away from mentally. Eighty minutes and no hook is a big ask for any listener. Ferrum Sidereum’s uniform construction does lend it a sense of unity, and ZU’s expert musicianship and occasional atmospheres do make the record a good background listen, but for the purpose of intentional, critical listening, it leaves much to be desired.

This is deeply disappointing to me, because Ferrum Sidereum can at times be simply transcendent. When it comes to shaping otherworldly and religious atmospheres, when ZU get it right, they get it right. “La Donna Vestita Di Sole” feels like a festival from another planet with its twisty sax riff, while the conclusion to the closing title track uses the dichotomy of furious palm-muted riffing and complete silence to make an ending both meditative and succinct. The one-two punch of “The Celestial Bull and the White Lady” and “Hymn of the Pearl” sees ZU at their most sublime, awash with delayed clean guitars and tribal drumming derived from the same sacred geometry as Lateralus, both stirring and refreshing to the mind and soul. There’s great material on Ferrum Sidereum, songs so good I can see clearly the greatness that ZU see in it, but material buried under about as much runtime of bloat as well.
I know there’s a world where Ferrum Sidereum clicks with me, but here and now it doesn’t. ZU are wildly talented musicians, and I know there are fans of instrumental metal who will gobble this up, but for me too much of what makes Ferrum Sidereum enthralling (its rich atmosphere and contemplative nature) is sidelined by what makes it boring (djent). “Hymn of the Pearl” may make a reappearance in December for SotY contention, but I think I’ve gotten enough of ZU’s latest as a whole. But I’ll keep an eye out for falling rocks, regardless.
Rating: Disappointing
DR: 5 | Format Reviewed: 320 kbps MP3
Label: House of Mythology
Websites: zuhom.bandcamp.com | facebook.com/vajrazu | zuism.net
Releases Worldwide: January 9th, 2026
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