The break rune works much as the heal rune, but in reverse. Break causes 1 hit point of damage/1 power. On non-living things 20 points of damage will destroy 1 AP. Victim’s will resist this spell with either their Will in the case of Mind attacks, or Con in the case of physical attacks. Break has a permanent effect, so duration is of no consequence.
Lyan has a Will of 6, and a Break Broo spell of 5. He casts Break Broo with a range of 2m (1 Spell Point), with no area of effect, and 10 intensities. The Broo has a Con of 8. His target number will be 6 [11 MF-5 Lvl+0 K]. He gains 4 successes and so has 7 drain [11 MF - 4 Ss]. He has now cast a spell with a power of 66. The broo resists 43, and takes 23 points of damage.
This is an permanent Spell.