Wait to use your physik till the 2nd half. Use FlameShrouding Cracked and Cerulean Hidden Tears and you will be a walking flame thrower.

Have your seals (erdtree and frenzied flame) upgraded to max or near max. Also you should have high Focus armor to prevent Madness buildup.

Setup:
Armor with high Focus ratings
Erdtree Seal
Frenzied Flame Seal
Primal Glintstone Blade
Fire Scorpion Charm
Godfrey Icon
Flock's Canvas Talisman
FlameShrouding Cracked Tear
Cerulean Hidden Tear
Flame, Grant me Strength
Golden Vow
Flame of the Fell God
Unendurable Frenzy