Hidden Gun

"It seems to be a kind of arma da fuoco - but as small as a hummingbird!"

- Leonardo da Vinci, regarding the hidden gun's design.

The Hidden Gun, also referred to as the Pistol, was one of the additional innovations of the Hidden Blade invented by the Assassin Altaïr Ibn-La'Ahad using the Apple of Eden.

After discovering the design schematics for the hidden gun on one of Altaïr's Codex pages, Leonardo da Vinci managed to craft one for the use of Ezio Auditore.

Description
The hidden gun consisted of a small firearm with a very short barrel that, if aimed properly, could kill a target from a distance. Though an excellent weapon for assassination from afar, it would give away its user's position immediately after firing, due to its loud discharge and smoke.

Up to 6 bullets could be held at a time, and could be purchased from any blacksmith. However, they were quite expensive, as one bullet cost 175 florins (149 florins with a full discount in Monteriggioni), which was three and a half times the cost of a throwing knife. Alternatively, bullets could also be obtained by looting dead guards.

Combat
The hidden gun took about a second and a half to completely aim, though it could be fired before it was fully aimed. Firing immediately without aiming was not advisable, as even at close range, it was highly unlikely to result in a hit.

Aiming the hidden gun within guards' lines of sight would automatically make them suspicious. When in combat against a small number of guards, aiming it for several seconds would also cause the group to lose morale and eventually flee, though this tactic was ineffective against Brutes.

Though not recommended, it was also possible to quickly switch to the hidden gun during a battle, and take a random shot from as close as possible to an enemy, before resuming the fight. Despite its low success rate, this method could potentially pick off immobile opponents, or quickly eliminate enemies without the need for counter-kills.

Advancements
Some time before the Siege of Monteriggioni, the aiming method of the hidden gun had been modified, and no longer required a trigger pull to be fired (an invisible mechanism similar to the hidden blade's). Though perfect aim was achieved much more quickly, the bullet could only be fired after the shot was fully charged.

Ezio also gained the ability to dual-wield the hidden gun alongside a medium, primary weapon; such as a sword or warhammer. It allowed him to seamlessly switch between short and long ranged combat in battle, using the hidden gun with his left and a sword with his right.

Ezio also used the hidden gun for counters and point-blank kills during close combat; for example, Ezio could sword-counter an attacking enemy, then instantly fire a shot into another, killing two guards at once.

After reuniting with Leonardo da Vinci in Rome, Ezio was able to purchase an upgrade to his hidden gun that allowed him to fire small poison darts from it, in addition to bullets. These darts were usable when the poison blade was equipped, and shared its effects, allowing him to quietly kill targets from a safe distance.

During his journeys in Constantinople, it is shown that Ezio had made several tweaks of the gun himself, as Leonardo went to France. The pistol could now be aimed and fired twice as fast, without the need to reload a bullet after each shot. Ezio has also improved his skill of aiming the weapon, only needing the aid of his other hand to aim at the first shot of a possible conflict zone, the next shots he fired could be aimed with only the hand equipped with the pistol. Besides that, Ezio could dual-wield the pistol on more weapons than just a sword and hammer, as well as other weapons.

Though not used by Ezio, Leonardo also created an alternative to the hidden gun called the hidden bolt, which could fire small crossbow bolts instead of bullets. This modification was requested by an apprentice of Ezio's, Francesco Vecellio, as Ezio had not allowed him to carry a hidden gun.

Codex Description
"Success! We have found a way to alter the structure of the hidden blade so that it can be used to launch small projectiles. It is capable of grievous damage – even from great distance. I confess, the means by which I came about the discovery was... risky to say the least. But I have found that in small doses, and with a focused mind, the Apple can be used without ill effect. Or so I hope.

"The knowledge of projectile combat is not new to us, having been observed amongst our Eastern neighbors. But their weapons were much larger – and insufficient for our needs. I have now found a way to miniaturize their designs, embedding their fiery weapon into a form that can be worn on the wrist.

"We have also refined the formula for combustible powder, such that common ingredients might be used. This is a dangerous bit of knowledge and it is best shared with only our closest allies..." -Altaïr in Codex Page 28.

Assassin's Creed II

 * The bullet Ezio fires from his hidden gun in the E3 trailer is marked with the Assassin insignia.
 * Often when the hidden gun is fired, a dog can be heard barking. However, no dogs are seen or mentioned in the game.
 * Both the hidden gun and throwing knives are disabled in the Secret Locations that require the player to chase after an Agile guard.
 * The hidden gun does not kill in a single shot during the battles with either Dante Moro or Rodrigo Borgia, though it is just as effective as usual when the player is required to assassinate them.
 * During Carnevale, Teodora suggests using the hidden gun to assassinate Marco Barbarigo, since its sound matched that of the fireworks being used.

Assassin's Creed: Brotherhood

 * Ammunition can be found when looting the bodies of any deceased guards, regardless of whether or not they are arquebusiers.
 * Four additional bullet slots (for a total of ten) can be purchased for 30 Units on Uplay.
 * For unknown reasons, counter-attacks do not use up bullet ammunition.
 * During a kill-streak, the player can hold down the attack button while targeting an opponent, causing Ezio to perform an automatic double kill with his sword and hidden gun, using up ammunition in the process.
 * The sound of the hidden gun more closely resembles that of a musket, rather than the cannon-like sound in Assassin's Creed II.
 * The Assassin apprentices' hidden guns (obtained upon reaching rank 5) use the same firing sound heard in Assassin's Creed II.
 * The apprentices' hidden guns are less effective than Ezio's, taking up to four shots to kill a guard.
 * When firing the pistol in the Memory Corridor (loading screen), no sound will be made, and the "blast" effect appears wider and brighter.
 * The hidden gun is a multiplayer ability.

Assassin's Creed: Revelations

 * Once the code for additional ammunition in Assassin's Creed: Revelations has been redeemed, Ezio's Hidden Gun gets an extra 2 bullets, Ezio's crossbow gets an extra 5 bolts, and Ezio's bomb capacity gets upgraded by 1 slot.

Others

 * The first recorded use of the hidden gun was by Altaïr, when he killed his rival Abbas Sofian during his return to Masyaf.
 * Due to connectivity features with Assassin's Creed II, it is possible to obtain a variant of the hidden gun that fires throwing knives in Assassin's Creed: Bloodlines.