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
Clear stage 25
Unlock Armoured Swordsmen
Unlock Feudal Knights
Unlock Royal Guards
Clear stage 10
Unlock Sergeant Swordsmen
Unlock Eagle Warrior
Unlock Warlock
Clear stage 1
Unlock Archers