Oslow Dostevich is a rugged man in his forties, described as being "built like a bulldog". He has salt-and-pepper hair and is often seen with a cigar. Oslow has a history with Bianca Odisko's family, specifically with her father, Dino, and was once a bodyguard for them. He appears to be a seasoned and dangerous individual, with "faded tattoos" on his forearms.

Oslow is shown to be a man of few words, often described as "economical with words". He is direct and unwavering in his intentions, as seen when he confronts Bianca about Cotton's involvement in her business, stating, "I'm not asking. I'm telling you as a courtesy". He is capable of swift and brutal violence when necessary.

Despite his intimidating demeanor, a more complex side of Oslow is hinted at through his relationship with Michael (Cotton), whom he appears to care for and protect. He also has a history with Bianca's mother, where he saved a young Bianca from witnessing her mother's murder at the hands of Dino. He acknowledges the dangerous nature of Bianca, referring to her as a "cobra".