Lyric discussion by HammerFloyd 

Cover art for Ruiner lyrics by Nine Inch Nails

While I do think it alludes to things like a sociopath and religion and abuse of power, I also think it plays a significant role in the story of the album. The Ruiner is Mr. Self Destruct, the mechanical voice inside his head who was introduced in the first song on the album. The way I see it, this song is almost like an ominous prelude to what the Ruiner is going to do to our protagonist, almost like a preparation. You get a feel for what the Ruiner does to people, and nothing can stop him. Though everybody has this voice inside their head, the Ruiner cashs in on depressed, desperate people, like our main character. So when his self-esteem and mental defenses begin to crumble, the Ruiner becomes more powerful, and nothing can stop him. Then in the next song, The Becoming, the Ruiner begins to take over.