Medievil - Lost Souls

First, you need to unlock chest in The Entrance Hall to release souls. After that is done, you need to locate a soul and then follow hint and release a soul. Check videos for easy solutions:

Brute Bruty (A Broken Blade)
Location - 
Solution - In front of Last Windmill in Scarecrow Fields

Ye Olde Olivara (Graveyard's Highest Hill)
Location - 
Solution - Return to the Graveyard

Baffy the Baffler (A Grass Dragon)
Location - 
Solution - The Asylum Grounds

Surgeon Sherman (Ring Around the Asylum)
Location - 
Solution - Inside the Asylum

Chen the Enchantress (Books by Firelight)
Location - 
Solution - Cemetery Hill

Peter Peter, Pumpkin Weeder (King-Free Pumpkin Patch)
Location - Pumpkin Gorge
Solution - The Pumpkin Serpent

Treviranus the Troubadour (Where Pantoms Play)
Location - The Pumpkin Serpent
Solution - The Hilltop Mausoleum (room where ghost plays, right of boss room)

Grave Keeper Kambic (A Guilding Angel)
Location - The Sleeping Village
Solution - The Graveyard

Gavin the Golden (Mellowmede Mine's Lethal Crystal)
Location - The Asylum Grounds
Solution - The Crystal Caves (Where green rune is, where big crystal shoots with the beams)

Sir Schmidt the Hermit (House on Pumpin Hill)
Location - Inside the Asylum
Solution - Pumpkin George

Darring D. Castro (A Gate Sealed by a King)
Location - 
Solution - The Haunted Ruins

Hopper the Legless (A Gate of Two Serpents)
Location - The Enchanted Earth
Solution - The Gallows Gaunglet

Son Jr., Son of Son Sr. (A Forest Merchant Uncaged)
Location - The Lake
Solution - The Enchanted Earth

Knight McKnight (Crumbling Into Pools)
Location - The Lake
Solution - Pools of the Ancient Dead (first big stone platform after first 2 bouncer enemies. You need to get to the far end where cart will chase you, and where one of the helmet is on the platform there)

Nautical Nachbaur (The Elephant Dragon Lair)
Location - The Gallows Gaunglet
Solution - The Lake (after you enter the frozen pool. Change to hammer and kill the rat)

Berrelman Badillo (A Bridge Between Crow's Nests)
Location - The Haunted Ruins
Solution - The Ghost Ship

Captain Coffman (A Clock for All Time)
Location - The Ghost Ship
Solution - The Time Device

Fisherman Formes (Fishing in the Sleeping Village)
Location - The Entrance Halls
Solution - The Sleeping Village

Sir Sloane (Zarok's Dragons Above)
Location - The Time Device
Solution - The Entrance Hall