Snake is a lean young guy with short white hair and a noticeable cowlick, covered in small patches of scales across his body.
He's the quiet type—barely speaks, and when he does, it's usually just relaying messages through one of his many snakes. Joker warns Ciel and Sebastian to watch out around him, noting that "Snake an' his friends are still shy" and mentioning their poison. That said, he's got a playful streak; fans have noted he flirts with Dagger through his snakes.
He clearly cares about the other first-tier members enough to give warnings and share information—he's shown apologizing to Doll after his snakes got loose. But he dragged his feet telling the others about Ciel and Sebastian sneaking into their tents, for reasons nobody really knows. Notably, unlike the rest of them, he doesn't call the group his brothers and sisters, and he doesn't actually go on their missions or seem fully clued in on what they're up to.
He also seems to actively dislike being put in charge of anything. When the second-tier members start asking where everyone is, he gives them bare minimum info before basically dumping the decision-making on them and bouncing.
Content compiled by AnimeList.moe from publicly available sources.