The Zodiac Spear is the most powerful weapon available in Final Fantasy XII. Its license is found in the bottom right of the License Board, just above Masamune. While being the strongest weapon available, it can be found fairly early in the game - provided certain chests are not opened. It costs 235 License points, and has an Attack power of 150.
Like all spears, Zodiac Spear grants the user +8 to evasion and has 4% chance of performing hit combos. Spears are among the faster weapons in Final Fantasy XII with 2.14s charge and 1.2s action time, second only to daggers and ninja swords.
As stated above, the Zodiac Spear can only be acquired if the player did not open certain chests earlier in the game, which are the following:
|Rabanastre||Treasure chest in Lowtown, outside of Old Dalan's place.|
|Royal Palace of Rabanastre||When sneaking into the palace (before getting the Goddess Magicite), there are several chests in the Cellar. The player must not open the chest in the southeast corner that contains an Elixir.|
|Nalbina Dungeons||One of the treasure chests in Nalbina Dungeons' Confiscatory, where Vaan, Balthier, and Fran regain their lost weapons and equipment, is forbidden. The forbidden one is the southernmost chest that always contains gil.|
|Phon Coast||At Phon Coast's Vaddu Strand there is a beach with 16 chests placed in a grid. The fourth chest that must not be opened is among these, so it is best to leave them all alone.|
Should none of the chests be opened, the Zodiac Spear will appear in the Necrohol of Nabudis, reachable via Salikawood's Corridor Of Ages, which means the King Bomb must be killed. The Zodiac Spear will reside in the Cloister Of The Highborn, in a group of 16 chests. When none of the characters are equipped with Diamond Armlets Zodiac Spear will be in the second chest from the left in the front row.
The other chests all contain a Knot of Rust, or a Dark Matter with a Diamond Armlet equipped. The 16 chests in Necrohol of Nabudis actually correspond to the 16 chests on the Phon Coast, except that Zodiac Spear can only be obtained in the Necrohol; if the player only claims the Zodiac Spear, they can later observe that one chest on the Phon Coast chest formation has disappeared.
Necrohol of Nabudis can be reached fairly early on in the game, after the player has obtained the Dawn Shard. The enemies around the place are on much higher level than the player party, however, and obtaining the Zodiac Spear so early can be rather counter-productive, as it will make rest of the game very easy.
A second Zodiac Spear can be obtained in an alternative site, the Henne Mines' Phase 2 Dig. Even if the mentioned forbidden chests named in the above chart are opened, the spear is still obtainable here. However, to unlock the site, at least 10 Espers must be acquired, and the Mindflayer Hunt completed. The player must speak to Geomancer Yugelu in Jahara to unlock this site, reachable via the Ore Separation.
The chest is hidden in a secluded area. The odds are heavily stacked against the player: chances for the chest to spawn is 10%, the chance the chest contains an item is 10%, and the item being the Zodiac Spear another 10% - meaning there is only a 1 in 1000 (0.1%) chance the spear will appear. In contrast to the original chest, the lead character must wear the Diamond Armlet in order to receive the spear.
There is a method exploiting the game console's predictable random number generator that guarantees a Zodiac Spear from the chest in the Henne Mines if certain conditions are met.
In the International Zodiac Job System version, the player no longer needs to beware of opening forbidden chests, as the whole concept was removed. In other words, there is no longer a Zodiac Spear to be found at Necrohol of Nabudis.
The Zodiac Spear appears as a weapon in Final Fantasy: The 4 Heroes of Light as the strongest spear. Zodiac Spear has an attack power of 22 and can be found in any of the bonus towers.