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