I am 95% certain that this is Gibbon, who was present at the skirmish at Hogwarts the night of Dumbledore's death. He was accidentally killed by Thorfin Rowle, who was aiming at Remus but missed.
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In the first photograph on that page, the belt he is wearing closely resembles the belt worn by the DE in your pic. If you look very closely, the clothes the two men are wearing are virtually identical.
