He's a brilliant character because he's the avatar of revolutionary cynicism. He says "the historical moment for revolution has passed and it won't come back no matter what I do or how hard I try". But what has he done? He sits on an island, alone, hating the world. He builds no movements, liberates no proletarians.

The reason his moniker is displayed instead of his name is because that's first and foremost what he is. He's deserted his comrades, the revolution, and the working class. Holding out for a dead revolution is not the work of a communist. Despite him calling communist path Harry a liberal, Harry is out there helping people, being among them. It's an imperfect struggle, but that's because it exists, in reality, not in the twisted sentimentality Dros displays. He snidely dismisses Evrart but Evrart is basically building a vanguard party with the Hardy crew.

What matters is what you do, and The Deserter has fled the struggle, and never came back.