Hello, hello, it's Ally again! And today I bring you Zacharias Smith! Your characters will hate him!
So Zac is basically a horrible, horrible person. He likes money and that's about it. Well, he also likes being mean to people and intentionally hurting them (emotionally, but given the chance probably also physically). He was a massive bully when he was in school and wouldn't even try to be nice. He doesn't rate nice very highly.
Whilst Zac wouldn't describe them as friends, he does have some former Hufflepuffs who put up with him he puts up with. They have mostly come to tolerate Zac despite what a massive asshole he is. However, if you need someone who your character absolutely despises? Zac's your man.
He works as an investment banker for Gringott's and has more money than any 22 year old should ever be allowed.