Wardens are trained healers who help Adepts endure the pain of wielding their radia-based weapons. For the Warden, this requires intensive research, experimentation and knowledge of radia crafting. For the Adept, having the support of a Warden means being better prepared to face the dangers of radia exposure.
Use Wardens with their Adept counterparts for best results. These two archetypes form a sort of symbiotic relationship. The Adept deals, the Warden heals.