Requires a (or Special Summon) to get it onto the field, consuming your summoning resources.
Does not protect against card destruction by effects (e.g., Raigeki).
You can Tribute this card to activate its effect. If you do, monsters you control cannot be destroyed by battle, and you take no Battle Damage during this turn. This effect can be activated during either player's turn. Key Strategies & Usage
Because it can be activated during either player's turn (as a Quick Effect), it is frequently used in "Stall" or "Burn" decks, such as those relying on Final Countdown , to survive long enough for a win condition.
Being a Warrior-type, it is highly searchable via Reinforcement of the Army or The Warrior Returning Alive , making it more reliable than many other defensive monsters.