athass_prkr
Even if it would be original if he was NOT registered for the tournament, we all know that the author will probably find a reason for him to participate. And in the event that Harry doesn't find a reason to enter himself (Arcturus might ask him to in order to improve his reputation on the international stage), there would be many potential culprits behind his forced entry. Dumbledore would do this because of their shared past in which he learned not to underestimate Harry and would see this as an opportunity to eliminate him. Voldemort should still focus on Neville, but he might consider entering Harry for his ritual. Grindelwald would be the least likely as he has had little contact with Harry and still shouldn't consider him a major threat. And then... there's Lily. Would she have any interest in doing this to her own son ? She seems cold enough to do that.