When you spawn in immediately cast Second Chance and then swap your left hand to empty. Swap you right hand to the Knight Sword after they come through the fog (so that it looks like you are drawing your sword for battle) and if you would like to now is the time to gesture. Swap the Cling Ring for Foe's Ring when Second Chance gets used up (so that your boss battle has a "second phase"). After killing your target swap your right hand back to the talisman (to sheath your sword) and gesture if you would like to. Don't forget to swap your left hand to the catalyst before you return to your world or you won't spawn back with full MP.
Self-imposed rules and clarifications:
No Grass. You have over 3000 HP anyway.
No Spice.
No Magic (spells that are cast with a catalyst).
Don't recast Second Chance.
Armor is up to preference, but you need the Silver Coronet to reach 100 MP and the Monk's Head Collar covers your face anyway.
Weapon is up to preference. Priest may not be the best class if your favorite weapon has a dexterity requirement.
You may dual wield. If you do, wait to swap from the catalyst until after your opponent comes through the fog for maximum cinematic feel.
No shields, block by two-handing (or with an offhand weapon that blocks).
Second ring is up to preference.