Watchers mentor slayers in everything from martial arts to demon identification to good etiquette at fancy meals. Most of them are british, which conveniently plays into everyone's existing stereotypes.
Watchers are good researchers, but they'll want to invest in some way to keep alive as well. A little dabbling in magic or sharpshooting is a common route, though watchers can become pretty good at just about any discipline.
Train costs at one hundred vitality: