If there are no level 4 or lower Monsters for you to use this card's effect on, don't worry. It can always use its own effect to attack your opponent directly. Equip a few ATK-boosting cards to pile on the pain.
This card combos well with "Mystic Plasma Zone", as it will gain a 500 ATK boost, as well as give whatever it's using it's effect on the same boost. Beware though, since DARK monsters are prevalent this combo might turn on you.
This card, if used properly, would work very well in a "Blackwing" Deck.
By combining this card with a Level 4 or lower "Blackwing" monster and "Blackwing - Sirocco the Dawn", you can deal heaps of damage, especially if you have many "Blackwing" monsters on the field at the time.
This card is also potent in a "Dark Blade" deck, which tend to focus on pumping up the aforementioned monster's attack and crushing your foe quickly.