I'm considering using Justin as a character in a fic I'm writing but as I flipped through the books and various fanfictions I realised that, as far as cannon is concerned, he's pretty underdeveloped. We don't even know his hair colour. All we are ever told about him in cannon is that he was down for Eton; he showed his mother Lockhart's books to persuade her that magic was a good thing, he's Muggleborn, he's in Hufflepuff, we don't hear about him after OOTP and he seems to be friendly with Ernie Macmillan.
We can however make certain inferences from these facts.
He was down for Eton - this gives us a reasonable idea of where he's from. More importantly, it gives us a possible view of his financial status. I'm not going to dismiss the idea that he could have been a scholarship student but I find it more likely that he was paying. With an entry fee of £1500 (roughly $2484.60) it is very likely that he comes from a fairly well off family. This brings up the interesting question - where is the money from? I've heard plenty of theories (inherited wealth, business, politics, military) but I'd be interested to know what other peoples theories are so that I can form a better idea.
Being down for Eton also means he was probably fairly intelligent. To get a place at Eton you need to pass an entrance exam - I have no idea how hard this exam actually is but they certainly wouldn't be admitting airheads.
He showed his mother Lockhart's books to persuade her that magic was a good thing - this could be interpreted in two ways. One is that he had heard of Lockhart before he became a teacher and the other is that it is possible his mother didn't start to approve of him being a wizard until he was beginning his second year. From the way he talks about her it does sound like he had to persuade her. Also, he only mentions his mother. This could be pure coincidence but it does open a window to the idea that his father may not have been a strong influence on his life at that point. Could he have been working away, disinterested, or even dead?
He's in Hufflepuff and he seems to be friendly with Ernie Macmillan - He's in Hufflepuff, the house for the hard working and loyal. However, this only gives us a glimpse into his true personality. Depending on his upbringing, he could display a whole variety of different traits. He's impressed by Harry's talk about the defeat of the basilisk in OOTP (which makes me wonder how much the victims were told about what occurred), he's clearly intimidated by Harry when he believes him to be the heir of Slytherin, he's very polite and complimentary about the trio when he first meets them, and he returned to Hogwarts despite the ordeal he suffered in second year and, interestingly, Ernie Macmillan had warned him to stay in their dorms on the day he was attacked yet he apparently ignored this advice and, for some reason, was roaming the corridors anyway. That certainly implies a wide variety of characteristics.
His friendships are another interesting point. He seems to get on well in cannon with Ernie Macmillan, Hannah Abbot and Susan Bones although whilst all of the others seem to have separate friendships with each other when not in a group Justin is only ever seen with Ernie. He and Ernie are clearly close in CoS and it is not unreasonable to assume that they remained best friends throughout their time at Hogwarts. Interestingly, in one of the DA meetings he's shown to be working with Luna Lovegood (somebody I can't imagine having many people wanting to be her partner) is this some sort of extra friendship, pity, or is he just on the fringe of his own friendship group. He is usually paired off with Susan (or occasionally Hannah) in fanon but I personally am not so keen on either of those pairs. It'd be interesting to explore his relations with other characters outside of the main Hufflepuff four.
He has no mention after OOTP - In HBP itís reasonable to assume that he was simply not mentioned because he had no significance but I speculate what happened to him during DH. He clearly could not have returned to school due to his blood status but that still leaves plenty of options open. He could have fled England. He could have played some part in the resistance movements. He could have stayed on the run in the UK. He could have been imprisoned for 'stealing magic', or simply imprisoned by Death Eaters or no real reason. He was probably injured either physically or mentally. He could have been killed.
All in all, he's a character with a lot of possibilities and very few facts. Does anybody have any thoughts?