The Barbarian Boss is the first boss in Castle Crashers. He is a very large, muscular barbarian that might be presumably the leader of the barbarians, or at least their best warrior. He enters from the right of the screen by knocking down a door, flattening a beefy barbarian. The fight starts immediately.
He carries a massive spiked heavy-shield attached to his back. The spikes on this shield have the ability to lunge out of it and retract again, allowing the Barbarian Boss to cover great distances to compensate for his slow movement. This can be easily blocked with a shield.
The Barbarian Boss, while slow, can demonstrate that he is also surprisingly agile. One of his attacks consists in slamming his shield into the ground, trying to flatten any enemies standing on its way. Instead of only lifting his shield back, he will use it to propel himself and perform a somersault to reach the other side of the battlefield.
As soon as the player has entered, a door will close behind and lock the player in with the Barbarian Boss. Eventually, regular barbarians will join the fight too. He can easily be defeated with juggling. After he dies, the player can hit the chest that crushes the Barbarian Boss, to open it up and litter the area with gold and other treasures. Once they are all collected, the ropes binding the Red Princess to the pole can be cut down and the kiss can be received. If there are two or more players, you'll have to fight over to determine who gets to kiss her.
- Giant Punch: The Barbarian Boss's basic attack is a punch which can be dodged or simply blocked with a shield. He will telegraph this move by drawing his arm back before performing this attack.
- Shield Spikes: The Barbarian Boss will momentarily block with the giant spiked shield which he takes from his back, and then the spikes on the shield will shoot out. These spikes have a good amount of reach but can effectively be blocked by the player's shield. This attack is also not very powerful. Both, the punch and the spikes, will knock the player to the ground if not avoided or blocked. The spikes will deal 10 damage on Normal Mode and 100 on Insane Mode.
- Shield Slam: Occasionally, the Barbarian Boss will swoop his giant shield over his head which, if it hits, will shove the character into the ground and the animation of a lever swooping back and forth will appear above the character's head, indicating the player to wiggle the / from left to right to escape. This attack can only be avoided, not blocked. Also, while the player is submerged in the ground, they can't take damage.
- Reinforcements: When the Barbarian Boss's health gets down to around 75%, barbarians will come from the crowd to join in the fight and, when killed, they drop fruit which can be used to heal the character. Only two barbarians will be in the fight at a time, and if one is killed, another will shortly take its place. Also, these barbarians will be damaged and knocked back by the Barbarian Boss's punch and spike attack.
- Toxic Belch: Once the Barbarian Boss's health gets below 50%, he will occasionally pull out a bottle and drink its contents, resulting in him burping which will both send out flames which will damage the player, and send the boss flying backward to the other side of the screen, which will also damage the character if they are in the way (the bottle can damage you if you get near it when it hits the ground).
During the fight with the Barbarian Boss, the player is restricted by doors to the left and right, and invisible walls created by barbarian hordes to the top and bottom of the screen. To the top of the screen, the four princesses are tied to stakes. When the Barbarian Boss's health is lowered to half, the Green, Blue, and Orange princesses are carried away, symbolic of how you only free the Red Princess upon winning.
When fighting him on Insane Mode, the Barbarian Boss moves much faster than he did previously, being able to easily keep pace with the player as the fight progresses. His punching, spike and burp attacks inflict far more damage, the slam attack seems unchanged, though. Also, he uses the burp attack more often. The animation appears to be somewhat skippy, for unknown reasons.
When the Barbarian Boss has been defeated, a large treasure chest will crush him. Giving the chest three hits will unlock it, sending its contents soaring and dropping treasure everywhere. This chest only gives you coins, coin bags and blue gemstones, which are valued at 1, 5 and 6 gold. On average, you can get around 100~200 gold. After the player is done looting, he then cuts the Red Princess' bindings, freeing her.
- This boss is also known as the "Husky Barbarian".
- When the Barbarian Boss hits the player with any attack other than a punch, the forefront crowd will cheer and jump into the air in excitement, partially obscuring the screen.
- When the Barbarian Boss launches his spikes and you block them, the Barbarian crowd will cheer the boss even though you weren't hurt. This is most likely a coding bug. The same thing happens if the boss hits another enemy barbarian.
- This boss is frequently used by mid-level characters to get money quickly, as he is no trouble for any character over level 10 and provides around 100~200 gold upon defeat.
- You could fight the beefy Barbarian instead of the Barbarian Boss as a boss in the original Castle Crashers demo.
- During the Barbarian Boss fight, a small, possibly child, barbarian can be seen in the crowd on the right side, near the exit.
- As the boss battle progresses, blood from the beefy barbarian will be slightly coming out from under the door on the ground.
- If you look, you can see that the princesses are taken away by thieves, fitting, albeit completely unlike the entire mass of the crowd surrounding you, possibly the same ones who bring the princesses to a cloaked Cyclops and Frost King in the Tall Grass Field level.
- It is possible to hit the Barbarian Boss from the ground while he is in the air to smash his spike wall on your face.
- When you lower the Barbarian Boss's health to a half, the three thieves can be seen from behind the wall, ready to capture the princesses.
- In the forefront crowd, two barbarians can be seen hugging smaller barbarians, possibly their children, meaning that they brought their children to see the fight.
- If beaten with the Barbarian, you will unlock the achievement/trophy "The Traitor".
- This boss is the easiest major boss in the game, you can kill him in a few seconds with a high-leveled character or an overpowered character.
- It is possible to get the Barbarian Boss stuck in a walking position by trapping him in the bottom-right corner.
- It's unknown what he looks like under the mask.
- The Barbarians in the crowd have varying colored masks. Most have light or dark tan, and one even has a pinkish tinted one. Regardless, they don't completely match the coloration of the ones that pop out of the crowd to fight or even that of the Boss himself.
- When defeated, the treasure chest that drops onto the Barbarian will spew out only Blue Gems and Gold. This may be because Barbarians in the past were from Sweden and the Swedish flag is Blue with a Gold cross.
- When The Barbarian reinforcements come out and if they get hit by the Barbarian Boss's Shield Slam, they will get grounded Into the ground the same way the player will get hit by this attack. They will get out of the ground quickly, this does no damage to the Barbarian, however. The Barbarian Boss will laugh, despite hitting his own ally. Barbarians can get hit by any of the Barbarian Boss's attacks, this does no damage to them. As the Barbarian crowd will cheer. This can be good for XP Farming.