(spoilers)
(6)Nagini
(11)Griphook
This seems like a fairly easy choice. Nagini is a snake who doesn't even have her own personality thanks to Voldemort sticking his soul in her. Griphook is actually pretty awesome in book 7, and a fascinating insight into how goblins actually think. Like...him being super pissed when the tiara gets passed from wizard to wizard instead of returning to the goblin that made it. Like...feeling that the sword of Gryffindor is not actually Gryffindor's, but was stolen. (Gotta wonder how Griphook reacted when the sword teleported out of his grasp and into the Sorting Hat so Neville could kill Nagini).
(3)Draco Malfoy
(14)Norbeta
A pet with no particular personality, versus a pretty solid character, who is not clearly good or evil (pretty damn rare for this series). Yeah, easy choice.
(7)Helena Ravenclaw
(10)Albus Severus Potter
Ooooh, the strongest of the epilogue characters! Someone who might actually deserve to win a match if he's up against a particularly weak opponent. And his opponent literally only exists in one chapter! Wait, no, Helena still has about triple his lines, and a pretty fascinating backstory, and even her more recent history is kinda interesting--it's fascinating that she confided in Tom Riddle when she didn't confide in anyone before him. Yeah, I can see arguing for Albus Serverus, but I'm leaning Helena.
(2)Fleur Delacour
(15)Hugo Weasley
Hugo...Hugo...Hugo...oh, an epilogue-only character. Does he have...a single line..at all? Like...I'm running some searches, and I literally can't find a quote from him. I don't even have much to say about Fleur; her personality seems to be "French" and "part Veela" and "likes Bill". But that's still better than...what's his name again?
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Cats land on their feet. Toast lands peanut butter side down. A cat with toast strapped to its back will hover above the ground in a state of quantum indecision