Beasts are fearsome. Creatures of the night perhaps; fangs glaring in the light and eyes ablaze. Uncontrollable and without remorse. The extension from beast to devil makes sense.

During the opening of Cary Fukunaga’s outstanding Beasts of No Nation, a cracked old lady reprimands a young group of boys. “Beasts” and “little devils”, she calls them. Their small trick, placing a large branch to block the road to beg drivers for money, is a far call from the brutal lifestyle of a child soldier.

Based on the book of the same name by Uzodinma Iweala, Beasts of No Nation charts the brief rebel career of Agu (Abraham Attah). After the threat of assault on his hometown, unexpectedly, he is forced to stay with his father and brother as they remain to defend it from looters. This plan soon turns ugly and Agu is suddenly alone, in a deep forest desperately trying to survive. This is where he meets the “Commandant” (Idris Elba), the leader of a group of loosely organised young men and boys. Carrying enormous knives and guns, with torn clothes and leaves almost sprouting from their small heads, this is a dangerous mob. But it’s all he has, and within minutes, Agu angrily shouts “Yes sir!” to his leader, under the assumption that he will gain justice for the death of his loved ones.

Taking its lead from Jean-Stéphane Sauvaire’s Johnny Mad Dog in 2008, Fukunaga’s vivid palette and sensitive portrayal ensures that no stone is left unturned. The detailed politics that exist is not the focus as names are often unknown and locations vague (Elba cast as simply ‘Commandant’ and the location is “an unnamed West African country”). This is about the vulnerability of a child, groomed and powerfully manipulated by others. Attah’s wide-eyed child is the picture of innocence with his family; a big toothy grin lighting up his face as they fall about laughing at the dinner table. But clutching an automatic, torn hat worn on his head like Rambo, his smile is no more. The silence of his compatriot, Strika (Emmanuel Nii Adom Quaye), is unnerving. But akin to Agu’s military man get-up, it’s all image. The scowl on his face and bloodlust in their eyes as they raid houses, shooting women and children, isn’t who they are. It’s who they think, and who they’re told, they should be.

Elba’s malicious power-hungry Commandant, in one stand-out sequence, pep-talks the youth army. Desperate to take command of a town by seizing a bridge, we witness his passionate language. He uses physical pressure to push against the lads, as they push back. They chant and move, psyching themselves up. There’s a religious fervour as they storm the town, killing those they don’t know but fuelled by a convincing leader. You feel the magnificent draw of this man, and you’re part of a team that feel like they’re winning, wielding such powerful weapons when proudly storming the streets. In training they’re shot at (with blanks) and believe they can’t be hurt. They’re not winning and they can be hurt. The rush of adrenaline is palpable and in these mesmerising scenes you simply can’t take your eyes of the screen.

Fukunaga subtly uses stylised techniques to heighten our senses, as drugs feed into the boys, giving them a sense of invincibility (despite the bodies that are piled up so often). His exquisite framing and use of colour is similar to the intelligent craftsmanship behind True Detective. We’re not mere observers and he wants us to feel as Agu does. The awkward hikes are disorientating, carrying bulky weaponry against the lush nature that surround the soldiers calls back to Aguirre, Wrath of God. Herzog’s direction of the slow descent into madness, as Spanish conquistadors tramples through the Andes. Agu’s vicious actions and macho-image is surely a form of madness?

Often, Beasts of No Nation isn’t afraid to disgust. Horrific moments that force you to look away (one audience member left in my screening, clearly shaken by the first murder committed by Agu) and remind you how little we are told of the real world events that still exist. This is passionate, brutal filmmaking. Beasts in the wild, these children are dangerous. But they are children, and the haunting eyes of Agu, before the credits close, will ask you what needs to happen for change.