Alphonse (21, casually androgynous man) is a scholar of the magical arts who convinced his parents nearly 2 years ago to send him to Neverwinter. Every month he writes them updates on his studies and travels as a devout follower of Oghma - most of which is fiction, with enough half-truths to cover his ass if they ever catch on. He actually does spend a fair amount of time studying this and that, even if it isn’t things he ought to know. He’s very interested in dark magic and its history: Necromancy, lichdom, charm spells, and all their worrisome implications. Most of his time is dedicated to carousing about town, drinking heavily with his fellow students, and getting up to no good.

He wears his family’s signet ring because it looks distinguished, but buries it in all his other gaudy rings. Family crest is a majestic rearing horse with a crown over it.
His official scroll of pedigree is mostly used to access high-end events and establishments, and isn’t terribly well looked after as a result. One corner is stained with wine.
A lover of fashion and frivolity, he’s never seen without some gaudy outfit and his expensive perfume. Perfume isn’t unusual for nobles, but he actually wears it because he’s terrified that he smells like horses.  

The Chevaliers are an old noble bloodline in Elturel, but not one of enormous repute or influence. Their name is known for top-notch pedigree horses, and for a long history of supplying the city’s cavalry, the Hellriders. Their Family crest is a majestic rearing horse with a crown over it.
Alphonse is the second-youngest of 4 siblings: Graiden (25, M, Rider), Braiden (25, M, Rider), Alphonse & Fontaine (19, F, stablehand).

Graiden and Braiden are strikingly handsome twins who delight in acts of bravery and chivalry, but who also delight in pushing their little brother into a lake and traumatizing him for life. Alphonse has been uncomfortable around water ever since.

Fontaine is a capable young woman who very much wishes for a life that doesn’t revolve around horses. She and Alphonse have always been closest with each other, and they keep in touch regularly. She does favours like covering for him when his lies fall through, and he returns those favours by formally inviting her to student galas (where other noble families might be in the market for superior horses!)

Back in Elturel, the Chevaliers are generally a pretty bland bunch and most other noble families don’t have any particularly strong feelings about them - they’re kind of like the horse girl in the theoretical classroom that makes up the noble echelon.
However, they do have a long-standing rivalry with an equally historical common family, the Bouviers, who breed premium cattle without any of the fanfare.  Their patriarch, Redoran Bouvier (50’s, M, human), is particularly prone to petty squabbles and stupid power-plays - all of which are reciprocated in full by the Chevalier matriarch, Fontaine Chevalier (50’s, F, Al’s grandmother). Some say this friction has existed between the families for many generations.

Isn’t exactly banned from the House of Knowledge, but most people there aren’t too fond of him since he’s an asshole and because he threw up in the main sanctum while partying once.
Lyon Sunshard (book-keeper, elf, appears late-40’s) has definitely seen and heard enough red flags to know Alphonse can and will get up to no good, but he’s seen a lot of shit in his time and honestly sees him as more of an annoyance than a threat.

All the mentors/staff at the University would probably agree that Alphonse gives off some intense Tom Riddle vibes (“I was in the library the other day, in the Restricted Section, and I read something rather odd about a bit of rare magic...”), but there isn’t really much they can do about that since he’s literally just following their curriculum.
He also attends various rich kid parties where he tends to get totally wasted, very cocky, and very stupid. He doesn’t really have any ‘friends’ so much as he has a regular crowd that he gets stupid with, and they all pretty much try to one-up each other.
Before the events of the adventure, Alphonse had been studying plenty of dubious magic, including entering a pact with an otherworldly entity in exchange for power. This stopped being a theoretical very abruptly one night when he did exactly that, because someone bet that he wouldn’t actually do it. The other guy had to run through the university naked the next day, so it was totally worth it.
While the stakes aren’t usually as high as they were that night, he does get into a lot of stupid bullshit bets, including one that he lost and subsequently had to go escort some lame guy somewhere the next day (while extremely hungover).