The way it handles 'learning' is pure system, but the 'knowledge' is pure lore. The protagonist doesn't intuitively know vampire weaknesses; he unlocks entries in a 'Vampire Codex' by experiencing things or consuming certain items (like blood of an elder). Each entry provides lore snippets and, crucially, mechanical data.
So, learning that running water is harmful isn't a folk tale; it's discovering that crossing flowing water applies a stacking 'Erosion' debuff that drains health. The mythical becomes mathematical, allowing the character to learn and adapt using a framework familiar to any gamer, which makes his progression feel earned and logical.