Final Fantasy III
This is Shiva's first appearance in a Final Fantasy game. A lot of other things had their first appearance too, like moglies!
The game is comparable to FF1 and there's not much story in it.
You can buy the Shiva summon magic for 700 gil in Leprit and Doga's Village. It also can be sold for 350 gil.
Shiva's design in the original FF3 graphics is really simple. Just screen flashes when she attacks and palette swaps for each differing attack.
Her 'true' form is really the Diamond Dust one.
However, Shiva's 3D design in the Nintendo DS remake fully used details from the Amano design.
Shiva was really strong in this game and had 3 different attacks.
The name of the summon magic spell itself is "Icen".
Depending on which Job type, she would have a different effect and differently colored sprite.
Hypno Beam: Sleep on all enemies
Icy Glare: Ice-Elemental attack on one enemy
Diamond Dust: Ice-Elemental attack on all enemies
Although there's fanmade translations out there, I still made this section.
Conjurer aka Caller is really Genjutsushi (magician-low summoner hybrid), Summoner is Makaigenshi (spirit summoner) and Sage is Kenja (wise man).