Before the fog
Upgrade your weapon and arrive with a full Estus supply. Frostbite punishes repeated exposure.
01 · STAY CLOSE
Work around his rear and sides. Take short attack windows and watch the frostbite meter rather than staying underneath indefinitely.
02 · CHARGE & BREATH
Stop attacking when he begins the charge sequence. Dodge each pass, then move behind him during the long frost-breath animation.
Common mistake
Trying to chase and hit him between charges.