I am still waiting to hear of guilds that do electric/fire damage besides the newbie skills of cosmicfire and blast which make those weaknesses so horrible, apart from cosmicfire/blast which are fire damage. (Which btw means that your "horrible weakness" is against a class who has spent 700 credits to specifically deal the damage your weak to).

Druids also have a very small lighting damage effect.
Merian weaknesses only come into play against blast and cosmic fire really.

Aside from artifacted damage knights like ixion and diamante but they two hit kill me anyway and would do the same to most people anyway regardless of weaknesses.

Ixion, Daevos, other people with lightning/fire runes?

Ohh when can I join the daevos guild