"Nothing warms a Wall Breaker's cold and undead heart like blowing up walls. A squad of them will make way for your ground units, and they will do it with a BANG!"
Level 1 & 2
Level 3 & 4
The Wall Breaker's appearance is that of a small skeleton that wears a brown aviator hat and has a small scar across its right eye. It carries a large bomb.
The Wall Breaker attacks by locating the nearest protected building and destroying its protective Wall by blowing itself up kamikaze style. It deals splash damage around its target and deals 40x damage to Walls.
Upon dealing damage, Wall Breakers will perish (regardless if they damage a Wall, building or enemy Troop).
Wall Breakers will attack Walls until all the Walls are gone, even if you put it far away from the Wall.
Wall Breakers destroy Walls faster than any other unit and make gaps for other units such as Giants to enter the opponent's base.
Wall Breakers will look for the nearest building/turret that is trapped (fully or partially) by Walls and target any Wall that is trapping them. The exact mechanic can be found in the video below.
Wall Breakers cost a fairly high amount of Elixir and, due to their low health, spamming Wall Breakers will result in many losses. To combat this, one or two Giants may be placed first to distract the nearby defensive structures. Wall Breakers can then be used to target Walls without being fired upon.
Giants and Wall Breakers make an excellent team: The Giants distract and in return the Wall Breakers destroy the wall. Then the Giants can move in successfully. All possible with teamwork.
Wall Breakers can be extremely effective if you deploy 2 at a time very quickly, and do a straight line of 2 Wall Breakers each.
Once Wall Breakers have destroyed a protecting Wall, the remaining Wall Breakers will proceed to destroy the protecting inner Walls.
Wall Breakers have small amounts of health so use them wisely.
Before you deploy Wall Breakers, place a couple Barbarians or Giants to soak up hits so the Wall Breakers don't die before they explode. It is helpful to place the Barbarians or Giants a short distance away from the target Wall so that splash damage from a Mortar or Wizard Tower won't catch the Wall Breakers as well.
Wall Breakers do splash damage, so it can also be used to finish off buildings close to the Walls.
Wall Breakers are no longer fooled by spiked or decoy Walls.
Wall Breakers will not target a Wall unless it can see a building behind it.
Note that Wall Breakers will not target single Walls. There needs to be at least 3 connected Walls for a Wall Breaker to target it, and it must be protecting a building fully or partially.
Having double layers of Walls is ineffective vs. Wall Breakers, as Wall Breakers deal splash damage that will destroy both layers of Walls.
Always try to keep less important buildings outside of your walls (collectors, builder huts, etc), so the enemy's wall breakers have to be placed farther away. This increases the chances of the Wall Breaker getting killed by your defenses before it blows up your walls.
Wall Breakers are not recommended to have in Clan Castles, since they blow themselves up to destroy the opponent's troop, however doing very little damage.
At level 3, the bomb that the Wall Breaker is holding becomes larger.
At level 5, the Wall Breaker's bomb turns golden.
At level 6, the Wall Breaker exchanges its bomb for a barrel of explosives, similar of that to a Giant Bomb.
The Wall Breaker is one of two Troops of which the picture in the Barracks resembles an upgraded version, the other being the Dragon.
If there are no Walls and you deploy a Wall Breaker, it will run to the nearest building and blow itself up. However, it will do much less damage to the building compared to what it can do against Walls, e.g. a level 5 Wall Breaker will do only 46 damage to a building, whereas it will do 1,840 damage to a Wall.
When Wall Breakers are sent to your Clan Castle, during an attack they will target the attackers and blow themselves up, which makes it a bad Troop to be donated for defensive purposes. When attacking, they are also pretty much useless, since they come out in large groups (like 5-10 at a time), blowing up a lot of Walls if they survive, but they may also die from a single Mortar shot. It is also quite rare for the remaining Wall Breakers to blow up the first layer of Walland the compartment inside.
Wall Breakers can be useful in the Clan Castle for low level players, though. If the low level player doesn't have Wall Breakers unlocked or the Wall Breakers are low level, a high level Wall Breaker or two in the Clan can really help them.
You can have a maximum of 120 Wall Breakers at one time in a complete set of fully upgraded Army Camps. This number increases to 137 if you include the 17 that can fit into a fully upgraded Clan Castle.
Note: Having this many Wall Breakers is highly discouraged (only second to an all-Healer army) as your army will end up breaking nothing other than walls.
Wall Breakers take up two spaces in your Army Camp as of the March 12, 2013 update. Prior to this update the Wall Breaker took up only a single housing space.