Grigoriy here is a member of the Drozdovs, a family of pureblood wizards who are rather well-known for their obvious and undeniable involvement in the dark arts, along with having invented quite a few new spells and potions over time. Other than this, there isn't much that is known about the family, and often nasty rumours surround them - being responsible for kidnappings, conducting terrible experiments, and overall things that make others want to avoid them. Thankfully, they usually stay in Russia.
Now, if you were to ask Grisha himself, he wouldn't confirm or deny any of these rumours, acting as if it's all rather amusing (it really isn't, but scaring people is entertaining). No, he's not a nice person, and don't expect him to act polite or refined, because having being raised in a rich household doesn't mean he cares at all for manners or any of that. He's blunt, easily annoyed, and his comments are often condescending, but there's also the part of him that enjoys things like Quidditch (he's a Seeker), smoking on rooftops, and -surprisingly enough- candy. In truth, he prefers not to talk about his family, as he'd rather avoid topics like how he'd much rather be at Koldovstoretz or how much he misses his sisters.
With all that has been said, you can probably already guess that Grisha isn't the friendliest person around, however, there are people he will definitely tolerate, and people whose company he will enjoy, although he's not one to hangout with those who aren't pureblood, for obvious reasons because he's a supremacists like that c': He just transferred, so he definitely needs to meet some new friends ;-;
As said before, pureblood supremacy is something in which Grisha is a firm believer, and he'll definitely go out of his way to insult someone if he thinks it necessary. He's also just generally easily annoyed, and while he's not prone to getting into fistfights, he'll hex or jinx someone without remorse. So yeah, a lot of room for conflict and enemies and all that fun stuff <3
Grisha is currently engaged and that is the actual reason why he transferred to Hogwarts, that being said, it's not like he cares much about it at all, and he's actually set on enjoying his time "single" for as long as he's able to... which means he's prone to make outs and flings and all that. He's not flirtatious, and a bit bold about what he wants, but if you want to throw a fling at him I'm definitely up for that <3 As far as we know, Grisha likes girls as much as he likes guys, and for now he has no endgame plot~
Basically, I don't have much preplotted with this kiddo, so please do throw kids at me because I'm very excited okay ;-;