Shiva

Shiva is a frequently recurring summoned monster that usually takes the shape of a blue woman. Her signature attack is "Diamond Dust" (sometimes called "Gem Dust"), which is a burst of Ice/Blizzard magic. Along with Ifrit and Bahamut, she is one of the only summons to appear in every main series game from Final Fantasy III through Final Fantasy XI.

Biography
Although enjoying regular appearances throughout the series, Shiva, like most of the popular summonable entities, has never been given any significant backstory. Shiva has occationally been shown as one of the more 'friendly' summonable entities. In Final Fantasy VIII for example, Shiva demonstrated a clear affinity for the main protagonist.

Physical appearance
Shiva's basic physical characteristics are that of a willowy human female with extremely pale skin and long, blue hair to invoke an image of ice and cold. This image is reinforced in later summon sequences by the addition of arctic winds, freezing temperatures and large ice crystal formations. Despite the cold, Shiva invariably wears only enough clothing to conceal her modesty, along with boots and other minor aesthetic pieces. She carries no weapon, and implements her main Diamond Dust attack with arm gestures and/or force of will. Later games in the series allow Shiva to carry out physical attacks in the form of kicks and punches.

Final Fantasy III
This is the first Final Fantasy introduce Shiva and the ability to summon. She can be acquired by purchase. The "white" effect causes Sleep. "Black" effect deals ice damage on one target. Full "Icen" summon deals large amounts of ice damage to all enemies.

Final Fantasy IV
Appears as a summon (or "call" in the first North American version) for the character Rydia after she rejoins the group in the Underworld).

Final Fantasy V
The Summoner job class has ability to call her. She is obtained in a tower behind Worse Castle. This is the first time Shiva appears as a boss and must be obtained by defeating her. Along with her are three Ice Commanders who also must be defeated.

Final Fantasy VI
Appears as an Esper, first encountered by the Returners in the Magitek Factory of Vector. After being drained of her power, she and Ifrit are disposed of by Kefka Palazzo in a waste chute. Believing they mean the two Espers harm, Ifrit attacks the group. Shiva soon senses Ramuh's power within them, and halts the battle. They then grant their abilities to the Returners. Her attack's Spell Power is 52, and she costs 27 MP to summon. She is unblockable. She teaches the following spells:
 * Ice X10
 * Ice 2 X5
 * Osmose X4
 * Rasp X4
 * Cure X4

Final Fantasy VII
Shiva materia is obtained from Priscilla of lower Junon after Cloud and company defeat the boss Bottomswell. She can then be assigned to a weapon or armor, and called upon in combat. This marks the first time Shiva has been seen in 3D.

Final Fantasy VIII
Available as one of two Guardian Forces assigned to protagonist Squall Leonhart at the start of the story. In keeping with Final Fantasy VIII's Junction System, GFs may be assigned freely to any party member. If Squall attempts to exit Balamb Garden before accessing the tutorial, Quistis will present both Shiva and Quezacotl to him before reaching the world map.

Final Fantasy IX
Shiva is an Eidolon that can only be summoned by Princess Garnet. The Opal is the jewel through which she learns it. According to notes left on the Summoner's Wall at Madain Sari, Shiva was first discovered by summoners in the form of a small child. As years passed she eventually grew into her more familiar and adult appearance.

Final Fantasy X
The Aeon Shiva's manifestation in this game is the result of dream-imagery provided by a Fayth (the sentient spirit of a dead person). Summonable entities in Final Fantasy X came under player control for the first time in the series, and replaced the player's own party members when called into battle. Aeons possessed a number of new unique attacks alongside the ability to attack and use magic and abilities, and could carry out their traditional main attack via the Overdrive system.

Shiva is acquired at the Temple of Macalania and is used in the battle against Seymour even before she is named by the player. When Lulu receives her Celestial Weapon, Onion Knight, Shiva will be able to break the damage limit of 9,999 HP. In the International and PAL versions of the game, Dark Shiva will appear as an exceptionally hard optional boss when the party attempts to re-enter Macalania Temple after escaping from Bevelle.

Final Fantasy X-2
Shiva reappears as a Dark Aeon the Gullwings must fight in Final Fantasy X-2, however since Macalania Temple is inaccessible during this game, she is fought when the party enters the Farplane.

Final Fantasy XI
The job class Summoner can unlock the "spell" Shiva upon completion of a certain quest. Only a summoner must go on the quest Trial Size Trial By Ice and defeat Shiva in a battle on Northern San d'Oria.

Once Shiva is aquired the attacks she can peform are Axe Kick, Blizzard II, Freeze Armor, Sleepga, Double Slap, Blizzard IV, Rush, and Diamond Dust.

Final Fantasy XII
This is the first Final Fantasy Shiva does not appear in since her first appearance in Final Fantasy III. Mateus takes her place as the ice-elemental summon. Although she does not appear in the game an airship appears that is named Shiva.

Motomu Toriyama, director for Final Fantasy XII Revenant Wings, has said Revenant Wings will have more summons than any previous Final Fantasy game. This could mean Shiva will have the chance to appear in a Final Fantasy XII title.

Final Fantasy Tactics
The job class Summoner earns this ability over time. Her Diamond Dust attack is a large ice elemental attack that spreads over a portion of the battlefield.

Final Fantasy Tactics Advance
The Summoner job class learns the ability to summon her through the Snake Staff item. Unlike in her other appearances where she appears with a revealing outfit, this incarnation of Shiva is shown in full armor with only the bottom of her face revealed. This version of Shiva wields a sword and shield, however, she does not use them to attack. Instead, she holds the sword vertically above her head, and cast an ice spell.

Final Fantasy: Unlimited
In the anime, Final Fantasy: Unlimited, Shiva makes two appearences, as a summon. The Soil Charge Triad (Soil is like the coloured bullet of a Magun, used to summon creatures) needed to summon Shiva is:

Followed by saying: "Shine! I summon you, Shiva!"
 * The cry of a soul without light, Forest Green
 * The soil that forbids the birth of life, Virgin White
 * To freeze all things, Ice Blue

Etymology
Shiva shares her name with the Hindu god, Shiva (also spelled Śiva). Shiva (in Hindu mythos) once saved the world by consuming poison, giving him/her blue skin around the area of the neck and throat. It should also be mentioned, that Shiva is a god of duality, meaning Shiva is both male and female (though more often thought of as male, giving his title), as well as god of life and death. Also, in paintings, Shiva was frequently mistaken for a woman, due to the long hair and facial features. What should be noted, is that there is a slim posibility, that the name was simply the Japanese way of pronouncing the word "Shiver", which is a possibility, given her icy nature.