Boss

A  is a powerful, normally unique enemy which doesn't respawn once killed. Bosses come in two varieties, main bosses (distinguishable as their name and HP are displayed at the bottom of the screen) and mini bosses, which are a lot weaker.

Main Bosses
While you need to kill most of the main bosses in order to progress in the game, there are a few optional ones.
 * Asylum Demon
 * Stray Demon
 * Taurus Demon
 * Capra Demon
 * Belfry Gargoyles
 * Gaping Dragon
 * Chaos Witch Quelaag
 * Moonlight Butterfly
 * Great Gray Wolf Sif
 * Iron Golem
 * Dark Sun Gwyndolin
 * Dragon Slayer Ornstein and Executioner Smough
 * Priscilla the Crossbreed
 * Seath the Scaleless
 * Pinwheel
 * Gravelord Nito
 * The Four Kings
 * Ceaseless Discharge
 * Demon Firesage
 * Centipede Demon
 * The Bed of Chaos
 * Gwyn, Lord of Cinder