Just have him make a willsave DC XX anytime he enters combat, if fails he will turn into a rage (barbarian rage) and will enter the fight in melee, even with his bare hands if that is the only choise open to him. He will not leave the rage untill everything is dead in 10 feet around him. To not attack a friend within the 10 feet he must make another willsave DC XX to prevent his bloodlust from attacking him as well. If subdued the effect will pass in 1d10 minutes.
Or just have him have a permanent chill touch on his bare skin as in touch. (could be powerfull but fun, no sweet lovin for ya lad
)
Or the SRD curses you can pick from!
Character must eat twice as much as normal.
Character must sleep twice as much as normal.
Character must undergo a specific quest (one time only, and then item functions normally thereafter).
Character must sacrifice (destroy) 100 gp worth of valuables per day.
Character must sacrifice (destroy) 2,000 gp worth of magic items each week.
Character must swear fealty to a particular noble or his family.
Character must discard all other magic items.
Character must worship a particular deity.
Character must change her name to a specific name. (The item only works for characters of that name.)
Character must change his class to a specific class if not of that class already.
Character must have a minimum number of ranks in a particular skill.
Character must sacrifice some part of her life energy (2 points of Constitution) one time. If the character gets the Constitution points back (such as from restoration), the item ceases functioning. (The item does not cease functioning if the character receives a Constitution increase caused by level gain, a wish, or the use of a magic item.)
Item must be cleansed with holy water each day.
Item must be used to kill a living creature each day.
Item must be bathed in volcanic lava once per month.
Item must be used at least once a day, or it won’t function again for its current possessor.
Item must draw blood when wielded (weapons only). It can’t be put away or exchanged for another weapon until it has scored a hit.
Item must have a particular spell cast upon it each day (such as bless, atonement, or animate objects).
And some more!
Character’s hair grows 1 inch longer (only happens once).
Character either shrinks a half-inch (a 01-50 result on d%) or grows that much taller (a 51-100 result). This event only happens once.
Temperature around item/Person is 10°F cooler than normal.
Temperature around item/Person is 10°F warmer than normal.
Character’s hair color changes.
Character’s skin color changes.
Character now bears some identifying mark (tattoo, strange glow, etc.).
Character’s gender changes.
Character’s race or kind changes.
Character is afflicted with a random disease that cannot be cured.
Item/Person continually emits a disturbing sound (moaning, weeping, screaming, cursing, insults).
Item/Person looks ridiculous (garishly colored, silly shape, glows bright pink, etc.).
Character becomes selfishly possessive about the item.
Character becomes paranoid about losing the item and afraid of damage occurring to it.
Character’s alignment changes.
Character must attack nearest creature (5% chance [a 01-05 result on d%] each day).
Character is stunned for 1d4 rounds once item function is finished (or randomly, 1/day).
Character’s vision is blurry (-2 penalty to attacks, saves, and skill checks requiring vision).
Character gains one negative level.
Character gains two negative levels.
Character must make a Will save each day or take 1 point of temporary Intelligence damage.
Character must make a Will save each day or take 1 point of temporary Wisdom damage.
Character must make a Will save each day or take 1 point of temporary Charisma damage.
Character must make a Fortitude save each day or take 1 point of temporary Constitution damage.
Character must make a Fortitude save each day or take 1 point of temporary Strength damage.
Character must make a Fortitude save each day or take 1 point of temporary Dexterity damage.
Character is polymorphed into a specific creature (5% chance [a 01-05 result on d%] each day).
Character cannot cast arcane spells.
Character cannot cast divine spells.
Character cannot cast any spells.
I like the permanent sounds or glow for a simpel curse.
Hope I helped ya out with it.
