The way this Build works is that you'll use Carian Slicer to its fullest by casting it with Lusat's Glintstone Staff and wielding Carian Glintstone Staff in the other hand or by using Contagious Fury from the Jellyfish Shield. Lusat's Glintstone Staff increases FP cost by 50%, but Carian Slicer only costs 6 FP to begin with, so you can get away with it here in order to boost damage.

You'll use Adula's Moonblade for larger enemies that are hard to hit with Carian Slicer and for AoE groups, and the damage of this Spell and all Cold Sorceries is boosted by 10% because of the Snow Witch Hat.

Carian Piercer is there for NPC invaders or actual invaders, as it has incredible hit boxes, and allows you to roll catch easily. Glinstone Icecrag is your ranged option that helps build up Frostbite, and deals decent damage, but is slow and doesn't have great range. You could swap this for Great Glintstone Shard if you want.

Freezing Mist is used to set Frostbite on tough enemies or Bosses to reduce their damage absorption, allowing you to deal more Magic Damage with your spells.

You can also add Zamor Ice Storm to this build, for its increased attack power and status buildup after patch 1.07.