Spectacle of Madness: The Insane Fighter has very little comprehension of the world around it, as its mental construct is completely broken. The unnerving yowls and bestial behavior can cause Fear in those within 60' who are affected by fear and fail a DC10 wis save. Failing the save will cause the frightened condition, rooting the person to the spot for that round and making it impossible for them to get closer to the insane fighter for the 1 minute duration, with a save at the end of each round. Making the save grants immunity to the effect for 24 hours. Fleshrender: The Insane Fighter's claw attacks are especially violent, untrimmed fingernails digging into flesh and rending back ribbons of bloody skin that cause a 2 point bleed, cumulative per hit, until a DC10 medical check or heal is applied to the injury (usually as an action). Uncoordinated: The Insane Fighter will always attack the nearest enemy, and will roll randomly to determine which one if more than 1 option is the same distance. Once all enemies are eliminated from an area of 30', the Insane Fighters will turn on anyone else, including another Insane Fighter, within 30'. If no other targets are within 30 feet, the Insane Fighter will attempt to attack any ranged enemy it can see that has hit it with an attack, nearest first; and if none exist, will revert to a passive state of mumbling and stumbling around for a random 30' move (you can roll a d4 per square to determine where it goes each 5').
Multiattack: The insane fighter makes two attacks per round. 1d4 twice to determine claw (1-2) or bite (3-4). Claw: Attack 1d20+5 , Damage 1d4+2 normal slashing -PLUS- a cumulative 2 point bleed per hit until the wounds can be stabilized with a medicine check or heal Bite: Attack 1d20+5 , Damage 1d6+2
The Insane Fighter will take an opportunity attack at the first, uh, opportunity. This is always a claw attack.
Humanoid victims of mind-damaging effects over a long term may devolve into Insane Fighters, a catch-all for people who may have been of any class or no class while sane. Insane Fighters have a feral toughness and are chaos personified, utterly unpredictable and incapable of rational comprehension. Their behavior may be passive or even catatonic when first encountered, but when a fight breaks out, you need a stat block for that :) Insane fighters attack with total abandon, using any weapon at hand or their own fists and teeth with no regard for personal injury or strategy of any kind. While they may attack as a horde or mob, there is no coordination possible on their parts; they have less rational sense than even a zombie would exhibit.
Any, but often in underdark or urban, where they may be prisoners loose in the stronghold.