If you could handpick a support band for The HU, then it would surely be SKÁLD. The only surprise is that they are French rather than Nordic. Everything else suggests they have arrived directly from some ancient ritual.

“Skáld” means “poet” in Old Norse, and their poetry comes wrapped in extraordinary atmosphere. “Ek skal riða” establishes that immediately, before “Myrkviðr” thunders into view. Most of them appear to be thumping drums, and by “Ó Valhalla” the chants seem capable of summoning the Norse gods themselves. There’s a hunting horn, too. Of course there is.

“Hross” has something primal in its horsepower, while “Draumakona” is appropriately mystical, Marie Potosniak’s vocals particularly ethereal. Yet by “Grótti”, you realise that something incredible is happening before your eyes. This is much more than an intriguing sound: the skill involved in “Himinbjǫrg” is unbelievable.

The male voices of Steeve Petit and Marti Ilmar Uibo give it another dimension, with the percussion becoming ever more forceful. By “Yggdrasill”, it feels as though they are beating the crap out of their drums. “Ljósálfur” supplies an appropriately stormy crescendo, and Potosniak’s violin is as ferocious as any axe you’ll find. A remarkable way to begin an evening.

At times thereafter, it sounds as though a pack of dogs is barking inside the Academy. On closer inspection, it’s simply the crowd chanting “Hu! Hu!” Pretty much from the second the band appear, those chants become part of the performance.

And let’s get this right immediately: “Lost Soul” is as metal as it gets.

“Horsemen” underlines something else. Watching The HU is watching a band who know they are on the cusp of something really special. They look happy to be here during “The Same”, and when they mix that sheer power with folk, they are unstoppable.

With “Upright Destined Mongol”, it isn’t merely the sound that’s huge. The production, the presence, the whole feeling of the thing is enormous. Gala’s throat vocals and the horsehead fiddles give the music its unmistakable character, but the impact needs no translation. “The Men” crushes everything in its path.

“Shadow” is heroically heavy, uplifting and ready for a headbanging. “Warrior Chant”, though, remains properly scary. Fists are in the air, metaphorical weapons drawn, and you can feel the force of it coming towards you. This is music that makes standing still seem an unreasonable proposition.

“Echoes Of My Father” proves they know how to leaven the mixture, while “Grey Hun” is big, meaty heavy metal entirely on its own terms. “The Real You” is screeching brilliance, and “Black Thunder” arrives with an ominous rumble. There’s fun in its ending, though, and Jaya’s flute brings another fascinating colour to a sound that keeps revealing more.

Then “Yuve Yuve Yu” has touches of Rob Zombie. No, really. That grinding insistence, the way the groove gets hold of you: there’s something there. The HU might sound unlike anyone else, but they understand exactly how to make a room move.

“Wolf Totem”, perhaps the song that introduced them to most of us, is big, brash and bold. “This Is Mongol” follows and might just be the best thing of the lot. Saving something that powerful for the end of the main set speaks volumes about what they have at their disposal.

They return with the promise of one more song. Their choice? Their own version of Iron Maiden’s “The Trooper”.

If you’re going to take on Maiden, you’d better come heavy. Believe it or not, The HU do exactly that, making it their own while retaining everything that makes it glorious.

On this evidence, you’ll be seeing them in arenas within the next couple of years. They are a metal band quite unlike any other metal band, but metal they most certainly are.

The overwhelming thought after this assault on the senses is that you don’t really know what has happened.

You just know the whole thing was brilliant.