This is a super-specific question, one that ideally I would have put in a simple Q-and-A thread if there was one, rather than giving it a thread of its own. How good of an idea is it to introduce a character by comparing them to another character....that isn't around or hasn't been introduced yet. I literally just started banging out some introductions today after forgetting about writing for a while. The intro I had in mind, and started writing, basically introduces an MC by contrasting them with someone else (whom the audience has not met, unless I actually ever write a prequel, but otherwise is described somewhat in following paragraphs. Again, only for contrast purposes though). Sorry if this is super-unclear. While introducing someone this way makes sense to me, who already has something of a "backstory" in mind, already knows about the characters being described, it doesn't seem too useful for the audience. So maybe it isn't the best idea.
What would matter to me most as you gave this comparison is that you do a good job of constructing both sides of the situation as the comparison goes on. You have to give me a file to reference for the comparison, so to speak, otherwise I'll get an Error 404. And if I never, ever have reason to know about {person being compared to}, then I'm not happy. That person doesn't have to be a player in the actual story, but their past presence needs to be a part of the story. These are my thoughts; mileage may vary.
It looks like you deleted the paragraphs showing your comparison. I'm not sure that's the best way to start a story, especially if one of the characters isn't even really part of the story. I could see this working if you are writing a character that is always comparing himself to this other character, but is the story about that? I'm not saying your approach can't work, but it's not one I would probably take to open a novel.
