I saw another episode with Kuchiki Byakuya. INTp would make more sense than INTj. That's because ISTj and INTj are both equally consistent in keeping their own promises to themselves, so the reasons why he's an unlikely ISTj will also make him an unlikely INTj. I also think he's more likely INTp than ISTp. It's because he seems to value Se (things I've already listed a couple of posts ago).