About one percent of the 6,000 NPCs are endowed with exceptional abilities. If you find one of them, recruit them right away. Some may have low loyalty ratings, but as long as you can hold on to them they can render you sterling service. Most are warriors, but some are religious personalities (Joan of Arc, for example), scholars (Chaucer, for example) and healers (as opposed to doctors, who will normally do more harm than good). The most coveted Mighty Man of all is John Hawkwood.