Orichalca

A fantasy world where humanoids are locked in a continual struggle to reclaim territory from the wilderness where monsters live. A society largely run by branches of the Adventurers' Guild, which controls the population of monsters through its members and doles out rewards appropriate to their abilities.   Health is not just a concept, it's an innate characteristic and everyone has innate sense of what their own is like. Skill is earned by practice, but is quantifyable and certain abilities can only be performed when one is Skilled enough. Everyone is born human, but when their Skill is high enough they can pick any humanoid species to turn into, in order to supplement their strengths. Jobs are not descriptions, they are rigidly-defined roles each with its own set of abilities that people learn. All this is just how the world works.   Setting for the story 'A Weapon Too Free' - but be warned that these articles might contain spoilers for the story!