"Ah, yes, children, come here, listen to the tales of the Order of the Angry Knights.
I was but a young imperial soldier when I first had the joy of seeing these relentless and terrible fighters, crashing into the enemy lines, shouting at the top of their lungs "ALWAYS ANGRY! ALL THE TIME! ANGRY FOR THE EMPRAH!", their yellow armor with red trims gleaming in the sun light, their banner of a face contorted in anger, the middle finger of its hand raised at the enemies. Chaos was ed." -common tale
It is said, the founder of this strange order of even stranger 'knights', if such a term could even apply for such berserker-like fighters, emerged from the womb of his mother armed and armored, holding a strange book called 'Battletoads III', a volume from which many weapons have been introduced to the army of our Empire.
The incredible rage of the infant culminated in a highly increased growth, reaching maturity in less than ten years. At that time, a warherd of beastmen attempted to attack the home of this being of pure uncontained fury.
It was there that the technique of 'improvised weaponry' would be first introduced to the world, as the man grabbed a Bestigor dedicated to abominable Khorne and used the vile beast as a primitive club, over the course of the whole battle screaming his battlecry, of which only the beginning has been reported: "FUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU"
as well as the ending, when he proceeded to kill the warherd's high shaman, by shoving the monster's own legs into its anus: "...UUUUUUUUUUUUUUUUUUCCCCCCCCCCKKKKKKKKKKKKKK YYOOOOOOOOOOOOOUUUUUUUUUUUUUUU!!!!!!!!!!!"
From then on, the village's young would be recruited by the man-incarnation of anger, following and learning from him the ways of rage, shouting and insulting, as well as the mysterious words: WEAPONS ARE FOR PUSSIES!
It was the year 2429 when the Rage-Given-Form first became of true renown, when he and his ANGRY warriors partook in the siege of turned-rebel Vorderbergen, having been hired by the citystates of Talabecland. It is reported how the angry-incarnation and his retinue stormed the northen gates of the city, by beating said gates to bits using the remnants of the southern gates as clubs.
From then on, the One-Who-Was-Angry and his Masses-Who-Were-At-Least-As-Angry kept on sweeping through the Empire, always seeking a good fight (or Tavern Brawl) to vent their neverending rage. However, which was actually unplanned, due to the next-to-nonexistent need of sustenance, as the Incarnation of Angriness had long since taught his disciples the technique only known as 'SHOUT INSULTS TILL THINGS GO YOUR WAY!', he and his 'army' had gathered massive funds...which they used to beat their enemies to death with.
But, the money kept flowing in faster than they could spend it on enemies, thus, soon the One-Bearing-The-True-Angriness learned that gold also had other uses. Such as, he found a wooden plank, shouted insults at the money long enough till it turned to nails, hammered the nails into the wooden plank and beat his enemies to death with it.
However, some time later he also seemed to learn even better how to use his money, today's massive fear of the beastmen before anything small, glittery and round being a testament to that fact, but He-Who-Was-Truly-Angry also soon bought a great many mortars and basilisks, only problem being that he insisted on buying them from a dwarven armor smith. It is assumed that he kept on shouting insults for several days till the dwarf managed to craft said cannons...somehow.
From then on, the more exotic (and feared) siege-weapons of the Angry 'Knights' were sighted on the battlefield, such as the feared Mortar Angrinator, a mortar that fires Angry Warriors directly into the enemy.