Bosses

Boss health scales with # of players at a rate of +80% base HP per each player past 1. For example, Evil's Protector has a base HP of 3000. With 3 players, its health total is 3000 + 2 * (3000 * 0.8) = 7800. Each boss is guaranteed to drop one of the items in the "drops one of the following" section. If you defeat the boss again, it will drop one of the remaining items until they have all been dropped. After that it will pick another random item and begin the cycle again

Appearance	Name	Drops
	Evil's Protector	Demonic Bar (12) 100%  Force of Wind 100% Drops one of the following:  Melee Foci 25%  Magic Foci 25%  Range Foci 25%  Summon Foci 25% First kill:  Demon Heart 100%
	Queen Spider	Cave Spider Gland (10-20) 100% Drops one of the following:  Spider Claw 25%  Spider Charm 25%  Webbed Gun 25%  Frost Piercer 25%
	Void Wizard	Void Shard (25) 100%  Recall Scroll (12-20) 50%  Travel Scroll (5-10) 50% Drops one of the following:  Void Staff 33%  Void Missile 33%  Magic Stilts 33% First kill:  Empty Pendant 100%
	Swamp Guardian	Drops one of the following:  Razor Blade 33%  Guardian Shell 33%  Dredging Staff 33%
	Ancient Vulture	Vulture Mask 10% Drops one of the following:  Vultures Talon 33%  Vultures Burst 33%  Vulture Staff 33%
	Pirate Captain	Deep Ladder Down 100%  Coins (300-500) 100% Drops one of the following:  Hand Cannon 33%  Pirate Telescope 33%  Spare Boat Parts 33%
	Reaper	Drops one of the following:  Death Ripper 25%  Reaper Scythe 25%  Reapers Call 25%  Shadow Beam 25%
	Cryo Queen	Drops one of the following:  Cryo Blaster 25%  Cryo Glaive 25%  Cryo Quake 25%  Cryo Spear 25%
	Pest Warden	Drops one of the following:  Venom Slasher 25%  Venom Shower 25%  Living Shotty 25%  Swamps Grasp 25%
	Sage and Grit	Drops one of the following:  Bow of Dualism 25%  Dragon Lance 25%  Dragons Rebound 25%  Skeleton Staff 25%
	Fallen Wizard	First kill:  Wizard Socket 100%

There are 3 bosses must be defeated to beat the game. They are Pirate Captain to unlock deep caves, Sage and Grit to unlock Desert Temple and Fallen Wizard, final boss in the game.

But with that, there are 2 bosses player should kill to beat the game. The first is Evil's Protector which drops Demon Heart and Demonic Bars. Second is Void Wizard which drops Empty Pendant.