Reification is the treatment of an abstraction as if it were a real entity or a physical object. It also implies the attribution of thing-like qualities to living aspects. The trouble is understanding the way this notion changes its implications in different contexts or in different scales or perspectives of any context.
The reification of power could mean something to the effect of “casting a large shadow”, but a more ubiquitous example would be The People. Here's a chilling comment from Che Guevara that provides insight into this:
“At the risk of seeming ridiculous, let me say that the true revolutionary is guided by a great feeling of love. It is impossible to think of a genuine revolutionary lacking this quality. Perhaps it is one of the great dramas of the leader that he or she must combine a passionate spirit with a cold intelligence and make painful decisions without flinching. Our vanguard revolutionaries must idealize this love of the people, of the most sacred causes, and make it one and indivisible. They cannot descend, with small doses of daily affection, to the level where ordinary people put their love into practice.” — Socialism and Man in Cuba
Among other things, take note of the Biblical aspects of this. In order for a human sacrifice to be a sacrifice, there has to be an "ordinary" love that is expended as propitiation in the process for redemption to be gained for a greater love of God. The implication of this being that the revolutionary who loves The People the most cannot help but sacrifice them in great number. The end logic of this being:
“Stalin returned to the Kremlin the next day, 1 July. Two days later he made his own broadcast to the Soviet peoples. His instincts served him well. He surprised his listeners by addressing them as ‘Comrades, citizens, brothers and sisters.’ No master of the Kremlin had ever addressed his people in such familial terms. … Stalin understood that the Soviet peoples were far more likely to lay down their lives for their country than for any Communist ideology. … He also ordered a people's levy—narodnoe opolchenie—to be set up. These militia battalions of ill-armed cannon-fodder were expected to slow the German panzer divisions, with little more than their bodies. … The untrained and scarcely armed People's Levy, the narodnoe opolchenie, was thrown into futile and murderous attacks, literally acting in the Russian phrase as ‘meat for the cannon.’ Altogether over 135,000 Leningraders, factory workers as well as professors, had volunteered, or been forced to volunteer. They had no training, no medical assistance, no uniforms, no transport and no supply system. More than half lacked rifles, and yet they were still ordered into counter-attacks against panzer divisions. Most fled in terror of the tanks, against which they had no defence at all. This massive loss of life—perhaps some 70,000—was tragically futile, and it is far from certain that their sacrifice even delayed the Germans at all on the line of the River Luga.”
—ANTONY BEEVOR, The Second World War
And so, what happens to the people in the People's Militia is completely irrelevant. Humanity could very well exhaust itself of life in this fashion, so long as the State remains.
Reflection time: Horrifyingly, that was a kind of sentiment that would have found purchase among many anarchists in the previous two centuries. Not the pinnacle it reached in the World Wars or any time after, but certainly the kernel of it.
“I have difficulty in keeping myself from falling back into reverie. I must form a definite plan of action. My purpose is quite clear to me. A tremendous struggle is taking place at Homestead: the People are manifesting the right spirit in resisting tyranny and invasion. My heart exults. This is, at last, what I have always hoped for from the American workingman: once aroused, he will brook no interference; he will fight all obstacles, and conquer even more than his original demands. It is the spirit of the heroic past reincarnated in the steel-workers of Homestead, Pennsylvania. What supreme joy to aid in this work! That is my natural mission. I feel the strength of a great undertaking. No shadow of doubt crosses my mind. The People — the toilers of the world, the producers — comprise, to me, the universe. They alone count. The rest are parasites, who have no right to exist. But to the People belongs the earth — by right, if not in fact. To make it so in fact, all means are justifiable; nay, advisable, even to the point of taking life. The question of moral right in such matters often agitated the revolutionary circles I used to frequent. I had always taken the extreme view. The more radical the treatment, I held, the quicker the cure. Society is a patient; sick constitutionally and functionally. Surgical treatment is often imperative. The removal of a tyrant is not merely justifiable; it is the highest duty of every true revolutionist. Human life is, indeed, sacred and inviolate. But the killing of a tyrant, of an enemy of the People, is in no way to be considered as the taking of a life. A revolutionist would rather perish a thousand times than be guilty of what is ordinarily called murder. In truth, murder and Attentat are to me opposite terms. To remove a tyrant is an act of liberation, the giving of life and opportunity to an oppressed people. True, the Cause often calls upon the revolutionist to commit an unpleasant act; but it is the test of a true revolutionist — nay, more, his pride — to sacrifice all merely human feeling at the call of the People’s Cause. If the latter demand his life, so much the better.
Could anything be nobler than to die for a grand, a sublime Cause? Why, the very life of a true revolutionist has no other purpose, no significance whatever, save to sacrifice it on the altar of the beloved People And what could be higher in life than to be a true revolutionist? It is to be a man, a complete MAN. A being who has neither personal interests nor desires above the necessities of the Cause; one who has emancipated himself from being merely human, and has risen above that, even to the height of conviction which excludes all doubt, all regret; in short, one who in the very inmost of his soul feels himself revolutionist first, human afterwards.”
—ALEXANDER BERKMAN, The Prison Memoirs of an Anarchist (1912)
Russian "peopleism" was of great consequence for anarchists at the turn of the last century, but its one thing that anarchists have left behind. (Even if it persists as an object of study and retrospection.) I'll leave you with this final excerpt, which really sums up my feelings about the reification of power and hopefully will find the same degree of impression in living anarchists as The People did in the past:
“The leftists persist in their well known cycle of provocation-repression-subversion which is all supposed to bring about revolution at some precise time in the future. But this conception of revolution is totally inadmissible because it means sacrificing men and women in order to mobilize others. Communist revolution does not demand martyrs because it does not need to make any demands. The martyr becomes the bait which attracts the followers. What would then be the use of a revolution that uses death as a bait in this way?  But then there is always someone who dies at just the right time (or the victim's demise may even be "facilitated"), and someone else goes around shaking the cadaver in order to attract the revolutionary flies.
Since the communist revolution is the triumph of life, it cannot in any way glorify death, or seek to exploit it, since this would be putting itself once more on the terrain of class society. There are some who would compare or substitute "those who fell in the revolution" with those who died in the service of capital: but it's all just the same old carnival of carrion!”
—JACQUES CAMATTE, Against Domestication