Entering the 10th year of the 3rd great ninja war many nations found themselves depleted of the traditional Shinobi and Samurai forces. Training to become such started at a very young age, but those that were not found at the suitable age where still taken in from training. But they couldn't be trained as well as 4 year olds could. The first Nation to attempt to circumvent this problem was the Hidden Sand. They started out modifying the Bow and Arrows into crossbows. But slow reload times and limited range and slow projectile speeds saw the hidden sand none existent sealing department combine the magnetism of the Kazekage clan into a prototype projectile launcher that would use magnetic forces to propel a kunai projectile into a rectangular space where one negative and one positive charged panel would propel the projectiles at high speeds at an enemy.

Its Debut at the 5th battle of gold mine village in the land of Rivers was sloppy and quickly fell into the hands of The leaf Shinobi.

Safely within the Armies of the hidden leaf, their wildly better sealing department they broke the weapon down into its bare components, and rewrote the whole magnetic formulae using a raiton based matrix over the earth/wind matrix used in the sands original design. Plus adding an autoloader connected to a sealing tattoo that would connect belly of the projectile made it for better reload, more efficient firing rate taking it from a 7 kunai a minute launch speed to a 24 kpm launch speed with a far superior charging time. Added into the handle (what we would call a pistol grip) was a chakra converter seal that converter neutral chakra into Raiton charged energy powering up the electromagnetic fields required to power the weapon. A chakra holding matrix for extended use of combat and an elongated 17 inch barrel for maximised conservation of energy. This improved design took the sand people by surprise during the Naval invasion that saw the battle of River city. The Kazekage seeing their chances of victory go up in smoke threw in the towel and surrendered to the Hidden leaf. A Disgruntled Sand shinobi stole the design for weapon and sold it to Kumo, and thanks to spy cells made its way to Iwa.

As time went on and The Cost for training traditional shinobi became too demanding and its easier training methods Kunai launchers would expand in variety across the elemental nations and During the last 5 years of the conflicts 1/3rd of the armies carried many Kunai launcher units and pure sharp shooter units with them.

One famous encounter was Between Kumo and Konoha during the battle of Shiroi-so woods where the only present Shinobi where Naruto Namikaze, who due to medical concerns was ordered not to use his Sharingan as his vision was becoming increasingly worst, his last student Shikamaru Nara, and enemy General Darui of the Black Lightning.

For 2 weeks trench lines and sniper posts kept the invading force out of the wood. Until Shikamaru Nara suggested the Infamous plan that became known as the Burning Tree charge, that killed 241,389 people including Shikamaru Nara himself. However it gave the hidden leaf a strong foothold and months later Cloud being split into 2 would considerably shorten the war by 4 years. This event would mark a strategic change in how the leaf fought the battlelines and new team formations where introduced. No longer would graduates be split into squads but groups of six with 2 marksmen and one kunai launcher operator (Think of it as marksmen their just handling your run of the mill 5.56 rifle and a kunai launcher operator as a machine gunner) 1 team medic and 2 Shinobi plus the jonin or chunin instructor.

This change in policy became known as the Nara formation in the name of the man who led the suicide charge. Who went on to win a post mortem Golden leaf medal. The highest military honor the leaf bestowed only ever awarded to outstanding individuals.

However this weapon brought in a new style of warfare and Naruto Namikaze even Developed his feared Indra's Arrow technique as a complementary Ambush technique that benefits from the launchers quick rate of fire. And also stacked up the casualty rates. The Final battle of the Third Ninja war, Battle of Red River named as such for the casualties and rivers of blood that pulled from the dead bodies claimed the lives of almost a million people. And neither Hidden Rock nor Hidden Leaf could gain an inch of ground during those final days. In this battle Itachi Namikaze would be fatally wounded and would later pass away from his injuries.

After the 3rd Great ninja war and the Golden Peace age began when the 4th Tsuchikage Namikaze Kurotsuchi in honor to her dead husband one the Hidden Leafs Most beloved heroes even after desertion and the battle between the Avenging Demon and the Lava mistress, released Konoha from Hidden Rock military control, and Releasing the truth of her own Marriage to Namikaze Naruto and giving Little Hitomi to Jiraiya in a show of trust. The Kunai launcher would become a lot more compact and became a defensive weapon that was cheap to make and was very wide spread, making it the top choice for home defense weapon in many parts of the world. The surviving hidden villages those being Sand, Rock and leaf formed an alliance called the Triumvirate. Later the Mizukage Yagura, would bring in the hidden mist into the alliance and encouraged peaceful relations between villages citing that the peace brough at the end of the 3rd ninja war was too precious and too costly to let go over petty squabbles and grudges.

The projectile weapons would prove Especially Useful when a white clone Army made from the cells of one individual rose in a madman's attempt to take over the world sparking the 4th Great Ninja War, where true to her Heritage Hitomi Namikaze, Daughter of Kurotsuchi and Naruto Namikaze would bring an end to the Madman's plan In an Amazing feat of Union between the Power of her Rinnegan and her ability with multiple elemental Kekkei Genkai she manifested, the Wood and the Storm release.