Spells in Planescape:Torment follow Advanced Dungeons & Dragons (AD&D) rules in that the caster must rest to replenish each spell used.
Most spell descriptions can be found at Gamefaqs P:T page, under Magic list, list by Kizor Nerdbringer. Information not found on this site is below.
Githzerai spells
Seventh Seal of Zerthimon: Missile of Patience
Level: 1
The spell information as printed in the game: Not very informative.
Range: ?
Duration: ?
Speed: ?
Area of Effect: ?
Saving Throw: Special
This spell becomes progressively more powerful the more it is cast. The first several castings will do 1hp of damage, before the missile is upgraded to a crossbow and (eventually) a powerful ballista.
Requirement: Seals of Zerthimon One through Six unlocked, 16 Intelligence to unlock the Seventh Seal of Zerthimon, and 19 Wisdom to comprehend it (give the summary of it to Dak'kon), whereupon two copies of this spell appear in inventory for The Nameless One and Dak'kon to use.
What follows is the text of the Seventh Seal.
"Know that the Rising of the People against the illithid was a thing built on many turnings. Many were the People who lived and died under Time's blade while the Rising of the People was shaped.
The Rising was shaped on a slow foundation. Steel was gathered so it might mark illithid flesh. A (sic) means of knowing the movements of the illithids were established, at first weak and confused, like a child gaining its voice. When the movements were known, then the illithids were observed. In knowing the movements, their ways of the mind were known.
When the illithid were known, many of the People were gathered in secret to learn the means to shield their minds, and the way to harness their will as weapons. They were taught the scripture of steel, and most importantly they were given the knowing of freedom.
These things were not learned quickly. The knowing of much of the ways was slow. And in all these things, time's weight fell upon all. From the knowing of one's reflection in the steel blade, to the knowing of the submerging of the will, to the knowing of seeing itself. All of these things and more the People built upon. In time they came to know the whole." - The Seventh Seal of Zerthimon, Planescape Torment, publisher: Black Isle.
Eighth Seal of Zerthimon: Zerthimon's Focus
Level: 3 Range: 50 feet Duration: 5 seconds per level of the caster Speed: 3 Area of Effect: 1 creature Saving Throw: None
Increases the chance of a Critical Hit.
Requirement: Seals of Zerthimon One through Seven unlocked, 18 Intelligence to unlock the Seventh Seal of Zerthimon, and 19 Wisdom to comprehend it (give the summary of it to Dak'kon), whereupon the two spells are available for The Nameless One and Dak'kon to use. Intelligence can be increased with Tattoos to learn access the Unbroken Circle of Zerthimon. Wisdom can separately be increased to comprehend the Circle, ie Intelligence tatooos worn for the first step can be removed and wisdom tattoos worn in their place. The same (probably) goes for other items. The maximum with only tattoos, and at the earliest opportunity (which is pretty much as soon as one can afford the tattoos), is +4 (one Revelation, and two Insights). However, a Cranium rat charm can be found very early on in the Trash Warrens, the next zone on from Mebbeth's hut, for +5 total.
The text of the Eighth Seal:
"Know that a mind divided divides the man. The will and the hand must be as one. In knowing the self, one becomes strong.
Know that if you know a course of action to be true in your heart, do not betray it because the path leads to hardship.
Know that without suffering, the Rising would have never been, and the People would have never come to know themselves.
Know that there is nothing in all the Worlds that can stand against unity. When all know a single purpose, when all hands are guided by one will, and all act with the same intent, the Planes themselves may be moved.
A divided mind is one that does not know itself. When it is divided, it cleaves the body in two. When one has a single purpose, the body is strengthened. In knowing the self, grow strong."
+Intelligence items
Tattoos
- Tattoo of the Magi. +3 Intelligence, twice as many 1st and 2nd level spells can be memorized. Buyable after the Nameless One achieves the 12th level specialization as a mage (which means levelling to 12th level as a mage first, and precludes receiving this specialization in another class)
- Tattoo of Logic Cubed. Consumed upon use. Special: Temporary +3 to Intelligence. Temporary -3 to Wisdom. Obviously one would have to wait for Mordrom to join the party (and get back to Fell's and buy it). Once used, and the Seal is accessed, one might need to wait for the Wisdom minus to wear off before telling Dak'kon of the import of the Eighth Seal, to get the scrolls (although most of the game guides recommend maxing Wisdom for the Experience point benefits).
- Tattoo of Revelation +2 (limit 1)
- Tattoo of Insight +1
Equippable items
- Kasseg, Cerebral Parasite. Special: +3 to Intelligence, +1 to Wisdom. Given by Fjhull in the Outlands. Can receive more than one, but the bonus is limited to the number equippable at one time.
- Ring Zero. Special: +3 to Intelligence, +3 to AC. Random drop in Undersigil after planeswalking.
Consumable items
- Cranium Rat Charm. +1 Intelligence etc.