Well, that was a great read. The AU was pretty believable (and I'm guessing the author might be Eastern Euro / Russian) and there were no obvious / glaring flaws in the story or the way it was presented. I'm not a fan of military / "groups of soldiers" stories, but this one kept me going. The source of Harry's powers was pretty obvious as a reader, but the extent of his powers and how they worked was the mystery.

Backstory:
The story diverges from

Spoiler

the Battle of Hogwarts. Harry couldn't destroy everything in time, and Voldemort put the entire country under a "curtain". People against Voldemort tried to ally with other European nations, but were unsuccessful and had to resort to running their own ops after the presence of Wizards was revealed to the Muggles and the ICW went from an organization that ensured the secrecy of magic to one that worked for its good use, and hence had to cut a deal with the now-Emperor Voldemort, and was rendered toothless.

Harry kept running Ops, many people from the Resistance died. He kept overdosing on Felix and got Ron, Percy and Ginny killed. He planned a secret mission into Hogwarts that was really for him to steal the Elder Wand.

Harry then became the Master of Death and could converse with the shades of people that he knew. He is trying to bring the curtain down with the help of a (side) character who is a muggle that has the ability to nullify magic. This side character is part of the Resistance and Harry engineers a self-suggestive plan to have them come over with a similar objective.

The worldbuilding was great, and so were the characters. The wandmaker Popovic and the squib guarding the garage were fleshed out well for side characters. The characters from Canon were treated well, they were some 20 odd years older, so there's bound to be some discrepancies, but you could definitely feel a shade of their younger selves (or maybe it's just me projecting). Either way, the author has some experience with writing fiction. Perhaps even in a different language.

The way the Hallows were handled reminds me of another fic, Hail Odysseus by Brennus. In both these fics, the resurrection stone

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allows the user to call back shades of the dead and prod them for information. In Hail, Harry truly was Master of Death, while in Beyond, The Hallows are just powerful artifacts.

Harry is described as someone who hasn't really trusted anyone for years, and so his explanations of the Hallows are stilted and in character, although somewhat useless. The skinny is that

Spoiler

the Hallows, when together, change properties. The wand respects the wizard who unites the Hallows much more, to the effect that Harry is practically invincible and has been for twenty years. The Cloak renders its user truly invisible/undetectable, and enables the user to hide other things in it. The Stone is a kind of collective-consciousness actualizer -- people who were alive left a print on those who are still alive, and this connection can be exploited to retrieve memories and information from people who are still alive, or from "shades" that are privy to people who are connected in this chain

As the first chapter shows, Voldemort knows Harry is a Horcrux and strengthens and fortifies his body, intending to turn him Immortal. Harry's appearance does not change over two decades. So, of course, it's pretty annoying when the fanfic ends right when the explanations and worldbuilding reach a significant point and Voldemort reveals himself. Still, I'm going to give it a 4.75/5.

The pacing feels (slightly) off because many of the plot points nursed in the beginning never come to fruition. But otherwise, really, no real flaws here.