A fire leader is a Tier 3 (T3) companion useful for his contributions to your 
Metal skills. He also provides a small amount of thermal and mechanical strength which helps overcome these resistances. He is best recruited by building an inn in the Renaissance Mountains (10% presence, 40 recruiting actions) or the Shortblades Mountains (7% presence, 58 recruiting actions). It is much easier to beat the terrain resistance in the Shortblades Mountains (20) than the Renaissance Mountains (30), so many people construct their inn in the Shortblades Mountains. Recruiting him requires an aggregate leadership of 32 or better, and your inn must have a prestige of 40 or better.