Unlock the following bonuses by performing the corresponding tasks:

BONUS - HOW TO UNLOCK
Agent Muriel Green - Complete "the den of souls" on hard difficulty.
Antadurunnu - Complete "the god seal" on hard difficulty.
Arnold Leech - Complete "al khali" on easy or normal difficulty.
Bishop Malthus St. Claire - Complete "crusades" on easy or normal difficulty.
Blind Behemoth - Complete "morituri te salutant" on hard difficulty without being incapacitated.
Brother William of Auxere - Complete "motley crew" on hard difficulty.
Centurion Textius Longinus - Complete "decadence" on hard difficulty without being incapacitated.
Child Crusader - Complete "crusades" on the easy or normal difficulty.
Corpses Behemoth - Complete "river of blood" on the hard difficulty.
Cpl. Simone Cole - Complete "the tomb" on hard difficulty.
Cpt. Devin Ross - Kill 50 enemies using melee attacks.
Cpt. Xavier Jones - Complete "man down" on hard difficulty.
Crossbowman Crusader - Complete "tortured souls" on hard difficulty.
Cultist - Kill 100 enemies using melee attacks.
Deceased Devin Ross - Complete "still with you" on hard difficulty.
Enlil - Complete "spiritual guide" on hard difficulty.
Exlposive Cultist - Disintegrate 50 enemies.
Flamethrower - Disintegrate 100 enemies.
Fr. Paul Rawlings - Pop 100 heads.
Gladiator - Complete "temple of pain" on hard difficulty.
Governor Cassus Vicus - Complete "rome" on easy or normal difficulty.
Grenadier - Kill 100 enemies using ghost bullet.
Inanna - Complete "skin" on hard difficulty.
Ki - Complete "flesh" on hard difficulty.
Legionary - Complete "the low road" on hard difficulty.
Lt. Abigail Black - Kill 50 enemies using ghost bullet.
Nanna - Complete "Blood" on the hard difficulty.
Ninlil - Complete "Skin" on the hard difficulty without being incapacitated.
Operation: Godseal - Complete "exorcism" on hard difficulty.
Psychic Commander - Complete "world war 2" on easy or normal difficulty.
Pyxis Prima - Complete "Sumeria" on easy or normal difficulty.
Sgt. Frank Delgado - Pop 50 heads.
Sgt. Wilhelmina "Billie" Church - Complete "al khali" on hard difficulty.
Sir Richard de Gray - Complete "out of the frying pan" on the hard difficulty.
Sumerian Puppet - Complete "flesh" on hard difficulty without being incapacitated.
The Jericho Team - Complete "rivers of blood" on hard difficulty without being incapacitated.
Utu - Complete "blood" on hard difficulty without being incapacitated.
Warrior Crusader - Complete "sewers" on hard difficulty.