Chaos of Battle

Chaos of Battle is an granted to Clerics using the  Priest of Tempus at first level. The ability was added in Baldur's Gate: Enhanced Edition. The potential companion Branwen is a Priest of Tempus and starts with this ability.

Priests of Tempus begin with one cast of the ability per day and gain an extra cast every ten additional levels, maxing out at 4 casts at level 31.

Effects
"Chaos of Battle applies bonuses to all allies and penalties to all enemies within a 30-ft. radius of the caster. The spell lasts 1 turn and will randomly affect the targets' Armor Class, Hit Points, THAC0, saves, or luck. The magnitude of the effect starts at 1 (5 for Hit Points) at level 1 and will improve by 1 (5 for Hit Points) every 6 levels of the caster."

Gameplay
For every creature within range, the game rolls randomly on the following table to determine which stat is affected:

Only one of these stats is chosen per creature.

Next, the magnitude of the effect is chosen based on the caster's level, increasing every 6 additional levels and maxing out at level 25:

This is the amount the stat is buffed (for allies in range) or debuffed (for enemies in range). The HP modifier is used when the initially chosen stat is HP.

A gameplay example to illustrate:


 * A level 8 Priest of Tempus casts Chaos of Battle during a fight with skeletons. The random stat chosen for the priest is Thac0, which gives the priest a +2 to Thac0 due to her level. The effect for one of the skeletons ends up being HP, which gives that skeleton -10 to its maximum HP. Another skeleton's chosen effect turns out to be save vs. polymorph, which gives that skeleton -2 to save vs. polymorph.

Multiple casts of Chaos of Battle do not stack, the new effect overrides the previous one. However, the Luck effect will stack with other similar effects such as Chant or the bard's song.