The key is getting the right distance when using Unendurable Frenzy against the 2nd and 3rd bosses. Try to start right when they sprout, then aim for the head when they lean in. Frenzied Burst can one or two shot the first boss.

RIP at the end unfortunately. T_T

Relevant Attribute Levels:
99 Faith, 60 Mind, 60 Vigor

Armor:
White Mask (10% buff after triggering Blood Loss)
Rakshasa Armor (2% buff)
Rakshasa Greaves (2% buff)
Rakshasa Gauntlets (2% buff)

Weapons:
Erdtree Seal (Casting Seal, Max upgraded)
Giant's Seal (Off hand Seal, used only for its 15% Fire buff)
Uchigatana (With Seppuku Arts, used to trigger Blood Loss buffs from Lord of Blood's Exultation, White Mask, and Red Feathered Branch Sword)

Talismans:
Red Feathered Branch Sword (20% buff)
Lord of Blood's Exultation (20% buff)
Fire Scorpion Charm (15% Fire buff)
Godfrey Icon (15% charged attack buff)

Crystal Tears:
FlameShrouding Cracked Tear (20% Fire buff)
Opaline Bubbletear (Can use whatever)