An aggro deck (aggressive deck) is one of the three basic deck types. This deck type aims to win by dealing as much damage as possible as quickly as possible, normally through the use of creatures. Aggro decks have three main elements: curve, threat density, and damage output.
Aggro decks generally have a low mana curve. Most of their spells cost either one or two mana. This low curve allows the player to use all the mana at his or her disposal every turn. It is normal to use spells with converted mana cost less than or equal to four in an aggro deck to avoid Wrath of God, since most aggro decks use creatures.
Threat density Edit
Threat density is the number of threats a deck puts out. Since an aggro deck relies on dealing as much damage as possible, players aim to play as many threats as possible per turn. A low mana curve allows the player to play multiple threats per turn (e.g., a one-drop on turn one, a two-drop on turn two, a one-drop and a two drop on turn three, etc.) in the hopes that the opponent will not be able to muster up enough answers in time.
Damage output Edit
Damage output is how much damage a card can do. At first glance, a Lightning Bolt seems to do more damage than a Savannah Lions, but in theory the Savannah Lions can do more damage: The Lightning Bolt will only be used once, but since the Savannah Lions is a permanent, it will be able to attack for each turn it is in play. After two attacks, the Savannah Lions has already done more damage than the Lightning Bolt. Of course, a creature with a higher damage output is better suited in a deck than a creature with lower damage output. Damage output is calculated by multiplying the creature's power by the number of times it will attack. Because of Wrath of God, damage output for creatures should only be calculated up to turn four. For example, a 1/1 creature played on turn one will do 3 damage; a 2/2 played on turn two will do 4 damage; a 3/3 played on turn three will do 3 damage; and a 4/4 played on turn four won't do any damage unless it has haste.