how good is frostbite? (darkmoon gs)

so i just beat the game with a rob and nagakiba powerstance bleed build,and in a month or so il get the dlc and i wanna try smth different in terms of build

i am between darkmoon gs,blasphemous blade and sacred relic sword

ik halo and fire dmg is good but i have no idea abt frost since i havenever used it

so is it good?

and another question : in a darkmoon gs build is it good to also be a caster or is it better to have the gs as the only damaga source?