He’s got the poison eating skill that the story is named for, he’s a really good alchemist, he’s a crazy good instinctual fighter, he gets a powerful and knowledgeable summon early on, he later awakens another ability that makes him really good at acupuncture and even better at making medicine, he’s super smart and has a crazy good memory, and so on and so forth

he kept trying to hide his skills several times over from the person who has already saved his life, offered him employment, and is currently supporting his growth as a hunter, when the rationale given for not wanting people to know his skills was that people get jealous and wary of people with S-rank skills and try to assassinate them. If Yu Jia wanted him dead he would be dead, and if she was going to sell him out she would already have done so, so the way he keeps withholding information or outright lying about stuff that frequently doesn’t even matter felt weird to me.