Here is the full list of all 14 Battle for Blood - there are Epic battles within 30 seconds! achievements.
Clear stage 60
Unlock Royal Knights
Clear stage 40
Unlock Wizard
Unlock Royal Guards
Clear stage 25
Unlock Feudal Knights
Unlock Armoured Swordsmen
Clear stage 10
Unlock Warlock
Unlock Eagle Warrior
Clear stage 1
Unlock Sergeant Swordsmen
Unlock Archers