Soul Transposition is the process of converting a Boss Soul into a Weapon, Ring or Spell.
In order to create items you must have:

• A Boss Soul.
• Must speak with Ludleth of Courland in order to start the transposition.

Soul Transposition

Required Item	Soul Cost	Transposed Item
Soul of Corrupted Gundyr	7,500	Atonement
	7,500	Accursed Sigil
	7,500	Eyri's Signet
Soul of Boreal Valley Vordt	5,000	Frozen Weapon
	5,000	Snap Freeze
	5,000	Vordt's Great Hammer
	5,000	Pontiff's Left Eye
Soul of Aborr	5,000	Dozer Axe
	5,000	Runic Seal
	5,000	Symbol of the Penitent
Soul of a Demon	5,000	Demon's Machete
	5,000	Demon's Great Hammer
	5,000	Demon's Fist
Soul of a Stray Demon	5,000	Boulder Heave
	5,000	Demon's Great Axe
	10,000	Spitfire Spear
Soul of the Rotted Greatwood	5,000	Pungent Blade
	5,000	Hammer of the Great Tree
	5,000	Greatwood Club
	5,000	Arstor's Spear
	5,000	Tainted Chalice
	5,000	Greatwood Remnants
Soul of a Crystal Sage	5,000	Soul Spear
	5,000	Crystal Hail
	5,000	Sage's Stiletto
	5,000	Crystal Sage's Rapier
	5,000	Scholar's Bow
Soul of the Cathedral Guardian	10,000	Morne's Great Hammer
	10,000	Med Heal
	10,000	Morne's Ring
Soul of the Deacons of the Deep	7,500	Dreg Torrent
	7,500	Whisper of Despair
	7,500	Pulsating Blade
	7,500	Cleric's Candlestick
	7,500	Deep Ring
Soul of the Blood of the Wolf	10,000	Conjure Watcher
	10,000	Wolf Knight's Greatsword
	10,000	Farron Greatsword
	10,000	Hornet Ring
Soul of the Old Demon King	7,500	Chaos Bed Vestiges
	7,500	Rockflesh
	7,500	Immolation
	7,500	Old King's Great Hammer
	7,500	Demon King's Greataxe
Soul of High Lord Wolnir	5,000	Black Fire Vestiges
	5,000	Black Serpent
	5,000	Wolnir's Holy Sword
Soul of Pontiff Sulyvahn	7,500	Soul Wave
	7,500	Orbs of Judgment
	7,500	Greatsword of Judgment
	7,500	Profaned Greatsword
	7,500	Ifanna's Signet
Soul of the Maiden	7,500	Blood Orb
	7,500	Blueblood Sword
	7,500	Quicksilver Shield
	7,500	Grufudd's Signet
	7,500	Life Ring
Soul of Yhorm the Giant	10,000	Yhorm's Great Machete
	10,000	Yhorm's Greatshield
	10,000	Ring of Punishment
Soul of Aldrich	5,000	Soul Instability
	5,000	Teleport
	10,000	Lifehunt Scythe
	5,000	Sword of Avowal
	10,000	Darkmoon Longbow
	5,000	Golden Ritual Spear
Soul of Rosaria	7,500	Bountiful Sunlight
	7,500	Divine Arrow
	7,500	Longstaff of Rosaria
Soul of the Dancer	7,500	Gwynevere's Abnegation
	7,500	Soothing Sunlight
	7,500	Dancer's Enchanted Swords
Soul of Consumed Oceiros	7,500	Crystal Storm
	7,500	White Dragon Breath
	7,500	Moonlight Greatsword
	7,500	Moonlight Butterfly Horn
	7,500	Consumed King's Staff
Soul of Champion Gundyr	7,500	Gundyr's Halberd
	7,500	Ofydd's Signet
	7,500	Prisoner's Chain
Twisted Soul	7,500	Cursed Ring of Evasion
	7,500	Cursed Ring of Vengeance
	7,500	Cursed Ring of Deflection
	7,500	Cursed Ring of Confusion
Soul of Dragonslayer Armour	7,500	Lightning Orb
	7,500	Perseverance
	7,500	Dragonslayer Greataxe
	7,500	Dragonslayer Greatshield
Soul of the Ancient Wyvern	10,000	Whirlwind
	7,500	Dragon Greatsword
	10,000	Drakewing Ultra Greatsword
	7,500	Dragon King Greataxe
	7,500	Ancient Dragon Halberd
	7,500	Dragon Bone Fist
Soul of the Ancient Soldier	7,500	Dragon Tooth
	7,500	Havel's Greatshield
	7,500	Havel's Ring
Soul of the Nameless King	7,500	Sunlight Spear
	7,500	Lightning Storm
	7,500	Blast Wave
	7,500	Storm Curved Sword
	7,500	Dragonslayer Swordspear
	7,500	King's Quarterstaff
Soul of the Mirror Knight	20,000	Thorned Greatsword
	20,000	King's Mirror
	20,000	Lightning Stake
Soul of the Twin Princes	10,000	Lothric's Holy Spear
	10,000	Lothric's Holy Sword
	10,000	Lorian's Greatsword
	10,000	Lothric's Scythe
	10,000	Prince's Shield
Soul of the Marauder	7,500	Dance of Fire
	7,500	Conjure Knight
	7,500	Fume Ultra Greatsword
	7,500	Fume Slated Swords
	7,500	Knight Slayer's Ring
Soul of the Lords	10,000	Firelink Dagger
	10,000	Firelink Sword
	10,000	Firelink Greatsword
	10,000	Firelink Rapier
	10,000	Firelink Spear
Soul of the Lordran Remnants	7,500	Ciaran's Tracers
	7,500	Greatsword of Artorias
	7,500	Dragonslayer Spear
	7,500	Greatshield of Artorias
	7,500	Leo Ring
Soul of Prince Dorthinus	7,500	Discs of Dorthinus
	7,500	Path of Frost
	7,500	Sacred Chime Hammer
	7,500	Fool's Sigil
Soul of Sister Friede	10,000	Blizzard
	10,000	Hail of Blades
	10,000	Mournful Flames
	10,000	Black Flame Arc
	10,000	Friede's Great Scythe
	10,000	Rose of Ariandel
Soul of Princess Yngvil	7,500	Rime
	7,500	Frostfire Volley
	7,500	Frostfall
	7,500	Ivory King Ultra Greatsword
	7,500	Frostflower Ring
	7,500	Wretched Pendant
Soul of the Demon Prince	10,000	Chaos Beam
	10,000	Cataclysm
	10,000	Smelter Sword
	10,000	Demon's Scar
Soul of Darkeater Midir	10,000	Unleash Magic
	10,000	Old Moonlight
	10,000	Black Star
	10,000	Obsidian Greatsword
	10,000	Frayed Blade
Soul of Slave Knight Gael	10,000	Halo
	10,000	Overwhelming Power
	10,000	Gael's Greatsword
	10,000	Repeating Crossbow
Soul of Halflight	10,000	Wrathful Orbs
	10,000	Holy Schism
	10,000	Wrathful Barrage
	10,000	White Birch Bow
Lothric's Holy Sword	10,000	Twin Princes' Greatsword
Lorian's Greatsword

Farron Transposition

Abyss Watcher Vernix allows to transpose the Farron Greatsword with different Weapon Arts.

Required Item	Soul Cost	Transposed Item
Soul of the Blood of the Wolf	10,000	Farron Greatsword (Parry)
	10,000	Farron Greatsword (Stomp)

Information here is accurate for version 2.15.