Feca disciples utilize a mixture of protective shields and glyphs to protect themselves and lay down elemental law on enemies. They may not top the damage charts, but their durable nature and flexible spellcasting system allows Feca to fit in anywhere that's needed.
Feca glyphs take a little bit of preparation to get going, but once they're up and running, they provide helpful area effects. Feca's water abilities focus on support, the fire branch is all about offense, and the earth branch is defensive in nature.
It seems as though the Feca are geared toward jack-of-all-trades players, so if that fits the bill for you, you may be interested in reading more on this class in the latest Wakfu dev diary.