The suicide spell was a spell capable of devastating the area immediately around the caster, at the cost of the caster's own life.
The Suicide Spell was cast by uttering "waíse néiat" (Be not) while referring to the caster's own body. The whole of the caster's body was then converted to explosive energy, utterly leveling the area around it and later poisoning the area with radioactive material. Only extremely powerful wards or defensive spells could protect one from its destructive energy, though the radiation could be cleaned through magic and its effects healed.
Role in the CycleEdit
The Suicide Spell was used by Galbatorix to kill himself and try to kill Eragon. Why Galbatorix tried to use this self-destructive spell rather than a more direct one aimed at Eragon himself is unknown - he may have been in so much pain due to his stabbing and the effects of the Empathy Spell that he decided it was best to end himself with his enemies. After its usage nothing was left of Galbatorix, the Citadel was ruined and Shruikan's corpse was burned away. It is possible that the same spell was used by Thuviel on Vroengard against the Forsworn during the Battle at Doru Araeba.
According to Glaedr, in describing the process of the spell, the atoms of the spellcaster are melted or split, which releases a tremendous amount of energy. In science, this is referred to as nuclear fission and is responsible for the atomic bomb, although is usually conducted with Uranium or Plutonium, not more common elements such as Carbon, Oxygen etc. This makes sense, as like on Vroengard, there was an "invisible poison," (nuclear radiation) which can also cause rapid mutations and evolution, which could result in creatures such as the Burrow grub, the Sundavrblaka, and the Angler Frogs if the magical nature of the explosion were to be taken into account. The high temperature of such a blast would have very well resulted in the walls glowing if not melting in Galbatorix's hall at the end of Inheritance. However, in many ways it is more similar to a matter-antimatter annihilation, in which all of an object's mass is completely converted into gamma radiation, with the amount of energy released defined by the equation E=mc^2.
It is worth noting that the actual power of such a blast would be exponentially larger than is depicted in the novels. From the description in the novels, the blast would equal no more than half a megaton. According to equation above (E=mc^2), a 55 kilogram elf would cause a 1.1 gigaton explosion, effectively sinking Vroengard. The same can be said for Galbatorix's use of the spell.
On the other hand, the spell may not have converted the entirety of either spellcaster's mass before the explosion or the drain of the spell killed them, thus accounting for the explosions being much smaller than one would expect if all of the mass were converted. Being at the epicenter of such a powerful explosion, they would still leave no trace of their body behind.
The inspiration for this spell most likely came from the Belgariad, as willing something to not exist in that series has an identical effect.