Koopa Bros.

"HI-YAAA! Here come the Koopa Bros!! Uh-huh! Oh yeah! We're the coolest of cool!"

- Koopa Bros.

The Koopa Bros. are a quartet of costumed ninja Koopa Troopas; they are followers of Bowser and his Koopa Troop. The Koopa Bros. consist of Green Ninjakoopa, Yellow Ninjakoopa, Black Ninjakoopa and the leader, Red Ninjakoopa. They are all egotistical and obsessed with being cool, though they have a great deal of respect for Bowser and each other.

It is mentioned by several characters throughout Paper Mario that the Koopa Bros. were originally inhabitants of Koopa Village, apparently living in it around the same time as Kent C. Koopa. Eventually, the Koopa Bros. grew tired of Koopa Village, finding its serene environment and lack of excitement boring. The Koopa Bros. eventually left Koopa Village and traveled to Koopa Bros. Fortress (which was apparently then in ruin), whose Bob-ombs they seemingly befriended.

The Koopa Bros. eventually became conceited and corrupted due to the influence of Bowser and Kammy Koopa, who had taken a liking to them. Enslaving the Bob-ombs inhabiting Koopa Bros. Fortress (which they seemingly then rebuilt), the Koopa Bros. worked them non-stop, and if they rebelled, they would be imprisoned. When Bowser stole the wish-granting Star Rod and imprisoned the Star Spirits, the Koopa King entrusted the elder Star Spirit, Eldstar, to the Koopa Bros.

''Super Mario-Kun
Prior to their appearance in Paper Mario, the Koopa Bros. appeared in Super Mario-Kun, a Japan-exclusive manga. In their first appearance in Super Mario-Kun, the Koopa Bros. appeared to attack Mario, Luigi, and Yoshi in a platform-filled area, taking on various disguises and utilizing shell-like shurikens in combat. The Koopa Bros. later appeared in the Paper Mario adaptation of Super Mario-Kun.

''Paper Mario
The Koopa Bros. first appeared in Paper Mario in Princess Peach's Castle, where they appeared to reassure both Kammy Koopa and Bowser that they could stop Mario, and also show them a technique, which impresses Bowser; the Koopa Bros. are later sent running from Princess Peach's Castle after informing Bowser that they didn't actually post someone to guard the captured Eldstar, a show of incompetence and lack of thought which infuriated Bowser.

At first, the Koopa Bros. simply attempt to stop Mario from reaching Pleasant Path and their fortress by disguising themselves as dark colored Toads and by blocking the path to those locations, saying that dangers lurked there. With help from Merlon, who sees through the Koopa Bros.' disguise, Mario is able to cause the Koopa Bros. to retreat. The Koopa Bros. attempts to impede Mario's progress in Pleasant Path as well, creating various obstacles and having various minions patrol the area.

When Black Ninjakoopa finds that Mario and his allies has reached Koopa Bros. Fortress, he alerts his brothers and they proceed to set about making various traps and obstacles in their home, all of which Mario passes. In a last-ditch effort to stop Mario, Red Ninjakoopa has his brothers set up three Bill Blasters on top of the fortress, which Mario manages to pass. Reaching the Koopa Bros. at last, Mario, before he could battle the Koopa Bros., has to battle their creation, a poorly constructed facsimile of Bowser. When their fake Bowser is destroyed, the Koopa Bros. attacks Mario using a whirling tower attack. Regardless, Mario still defeats the Koopa Bros., who are sent tumbling into the prison of their own fortress, incapable of escaping.

At Mario's House, a letter from the Koopa Bros. meant for Mario is found; the letter is filled with threats uttered by the Koopa Bros. at Mario, with the Koopa Bros. swearing revenge on him. Also, for a short while after their defeat, the Koopa Bros. are found in the prison of their fortress. Later, the Koopa Bros. evidently manage to escape this prison, as, if Mario visits it later, the Koopa Bros. are gone.

The Koopa Bros. later appear at Bowser's Castle under the employ of the castle's third living door; the Koopa Bros., who claim to have become stronger (even renaming themselves "the Super Ultra Mighty Koopa Bros. the Great") prepare to fight Mario when Jr. Troopa appears and simply knocks them aside easily.

During the ending parade of Paper Mario, the Koopa Bros. appear riding a float constructed out of the remains of their old Bowser construct. As the Koopa Bros. strike a pose, several Bob-ombs appear and explode near them, covering them in soot.

Red Ninjakoopa
The leader of the Koopa Bros., Red Ninjakoopa has authority over his siblings and seems to come up with their plans. When Mario reaches the roof of the Koopa Bros. Fortress, Red Ninjakoopa has the other three Koopa Bros. open fire on him with a barrage of Bullet Bills.

Black Ninjakoopa
Black Ninjakoopa is the possible second-in-command of the Koopa Bros. and the one seen apart from his brothers most often. When Mario reaches Koopa Bros. Fortress, it's Black Ninjakoopa who reports this to Red Ninjakoopa and his other brothers, who increase their bases's security accordingly. Additionally, when Mario first enters the chamber where he battles the Koopa Bros., it's Black Ninjakoopa who appears to greet him, before leaving with Red Ninjakoopa to pilot the Bowser???.

Notably, Black Ninjakoopa is discolored blue in the official artwork. This was likely a mistake on the artist's part.

Green Ninjakoopa
Upon being alerted to Mario's arrival at the Koopa Bros. Fortress by Mario, Green Ninjakoopa takes defense precautions and has a key sealed away and guarded. When Mario finds Green Ninjakoopa while he is doing this, the Koopa Bro. taunts Mario and fled.

It is interesting to note that Green Ninjakoopa is one of the few battle-friendly Green Koopa Troopas in all of the Paper Mario series, save for the Green Koopa Troopas of Super Paper Mario (which even allowed normal green Koopa Troopas to be fought in its The Bitlands area). He is apparently the third-in-command of the Koopa Bros.

Yellow Ninjakoopa
When Mario gets deeper into the Koopa Bros. Fortress, Yellow Ninjakoopa sets a trap for him; when Mario hits a rigged ? Block, a trapdoor opens beneath him and sends him falling into the Koopa Bros.' dungeon; as Mario falls, Yellow Ninjakoopa taunts and jeers at him.

Ironically, Yellow Ninjakoopa's plan of trapping Mario in the dungeon backfires, as Mario meets Bombette in the dungeon and also manages to break several other Bob-ombs out of it. He also appears to be the last-in-command of the Koopa Bros.

Trivia

 * The Koopa Bros. are obvious spoofs of the Teenage Mutant Ninja Turtles, being turtles, ninjas wearing similar colored costumes and having a similar group name.
 * The song that plays when the Koopa Bros. are fought is a remix of the Hammer Brothers battle theme from Super Mario Bros. 3.
 * The music that plays when the player first enters the Koopa Bros'. chamber is the music that plays in Donkey Kong when Donkey Kong climbs up the ladders in the intro.
 * The song that plays when the Koopa Bros. fired Bullet Bills at Mario and company is a remix of the Koopalings' Airship theme from Super Mario Bros. 3.
 * The song that plays when Mario first arrives at the outside of the Koopa Bros. Fortress is the Fortress theme from Super Mario Bros. 3.
 * After defeating the Koopa Brothers, much later in the game, Mario is asked a question by Chuck Quizmo about which Koopa Brother doesn't exist. The right answer is Blue Ninjakoopa, and the other two options are Black Ninjakoopa and Red Ninjakoopa.
 * The Koopa Brothers are the only chapter bosses (aside from Bowser) that were seen again, prior to the ending parade. They are also the only bosses to send Mario a letter.
 * A Koopa Brother can be seen watching the Chuck Quizmo show.