Barbarians wield short swords and have blond hair and amazing moustaches.
The Barbarians are a great option to use against enemy troops and Crown Towers, as the Barbarians have a moderate amount of hitpoints and damage, and are perfect for attacks with other tanks. Although very effective against single target troops like the Prince, Barbarians are susceptible to spells and troops which do area damage due to their slow move-speed. Their slow attack speed also leaves them vulnerable to swarm cards such as the Skeleton Army.
They are excellent for taking out low numbers of enemy troops such as the Prince or Musketeer on the player's side. The 4 Barbarians will quickly eliminate the target if they are dropped directly on top of it and surround the unit.
A successful defense with Barbarians will also make for a powerful counter-push; tank for the barbarians for a threatening push or use them to tank for a glass-cannon, which also results in a threatening push.
They can also defeat a splash unit if placed directly on top of the unit but failing to surround the splasher with Barbarians will cause them to take more damage than necessary. Note that this is ineffective against a Bomber, a charging Dark Prince or a Valkyrie, as they have 360º splash.
The Barbarians can be effectively countered by most splash troops such as the Bomber and Wizard. However, be sure to place them at a distance so they are not immediately mauled. However, you must be careful as the opponent can use a Tornado or Freeze to immobilize or destroy the splash attacker, allowing the Barbarians to devastate the Crown Tower. Fire Spirits can cripple Barbarians, and are also very cost effective. Note that Fire Spirits alone will usually be unable to completely eliminate an entire group of Barbarians. Finish the Barbarians off with other troops or allow the Crown Towers to finish them off.
A powerful counter is the Fireball; the damage and radius of the spell is more than enough to severely damage all the barbarians to such an extent such that they can be one-shotted by the Arena Tower.
Poison can also be an effective counter to use. Its Damage over time will eliminate, or deal high damage to, the Barbarians and any supporting troops. However, the Barbarians will eventually walk out of the Poison with a fair amount of health left.
If the Barbarians survive, try supporting them with a tank in front to get some use out of them.
Rage used with Barbarians can do severe damage to a Crown Tower, as it is hard to stop because Rage increases movement and attack speed. The Barbarians have high damage and can make short work of a tower before the opponent stops them.
Deploying Barbarians down the lane is futile and is essentially a waste of five Elixir unless the opponent is short on Elixir simply because of the numerous counters to the Barbarians and their slow move-speed. Always be ready to deploy a support troop along with the Barbarians, such as a tank, spell or glass-cannon to get the most value out of them.
It is a very bad idea to ignore them as they will be able to destroy a Crown Tower by themselves.
They are the best troops to take out enemy tanks due to their numbers (4 of them), moderate damage, and ability to tank most spells. Support troops will have trouble killing them due to their hitpoints. If the combo happens to be any ground-based splash damage card + ground-based melee tank, wait for the troops to cross the river. As soon as they cross, immediately drop the Barbarians upon the splash card. They will surround and destroy it quickly before moving on to eliminate the now unsupported tank. This can result in a large positive elixir trade. However, if there is more than one splash unit, the Barbarians are likely to be taken out immediately.
The Barbarians card was released with Clash Royale's soft launch on 4/1/16.
From the Knight's description, Barbarians are said to be distant cousins, due to their physical similarities, especially their awesome mustaches. However, in the card image, Barbarians have blue eyes, while the Knight has brown eyes.