Mass Death

Mass Death - also known as Mass Kill - is one of the most potent spells of death.

Spell Description
Should all other ways of dealing with the caster's foe fail, if the party is surrounded by enemies ready to strike them down, then - and only then - should Mass Death be used. Once cast, it leeches on the life force of the caster and their companions, to create a literal wave of death. The end result is as amazing as it is horrible. All the foes in sight are instantly slaughtered. The huge dangers involved in this spell should be a warning, since it could easily cause the caster's death if already weakened!

History
The spell worked somewhat differently in earlier ages. Such powerful magic was first developed during the Age of Darkness in Ultima III, where the spells P and Zxkuqyb killed multiple foes but had no drawbacks apart from high mana consumption. Research into such spell then was stopped and it was not until the time of Ultima VI in the late Age of Enlightenment that this type of spell resurfaced. In that time the spell was being cast towards a destination of choice, where it would explode outward, killing everything in its vicinity - even the caster if they were too close.

It was only at the dawn of the Age of Armageddon that the version of spell seen nowadays was developed.

Trivia

 * Balthan, in Lynn Abbey's Ultima Saga, illuminates scrolls for the wizard Felespar. The ones he was working on when Blackthorn kidnapped the councilman were Eighth Circle magic, including spells that can "slay a man wherever he stood".
 * In game mechanics, in Ultima VII the spell reduces the hit points of the party members to a minimum, the screen turns red for 1-2 seconds, then all foes die. During these seconds, the party is therefore left almost defenseless.