Base Attack Bonus:  +3
Alignment:  Any non-lawful
Special:  Must not have any levels in Barbarian or any other class that grants a rage type ability.
Cursed:  The DM must decide if the Berserker is cursed when the player first takes the prestige class.  Most cursed berserkers are said to be "inhabited by the spirit of rage."  Just what that means in each campaign will depend upon the DM.  Often, people look upon the cursed berserker as cursed by the gods, but a few primitive cultures call cursed berserkers the truly devout.

Hit Die: d12

Class Skills
The Berserker's class skills are Climb, Craft, Handle Animal, Intimidate, Jump, Listen, Ride, Swim, and Survival.

Skill Points at 1st Level:  (4 + Int modifier) x 4
Skill Points at Each Additional Level:  4 + Int modifier
Level Base
Fort Ref Will Special
1 +1 +2 +0 +0 Rage 1/day
2 +2 +3 +0 +0 Uncanny dodge (dex bonus to AC)
3 +3 +3 +1 +1  
4 +4 +4 +1 +1 Rage 2/day
5 +5 +4 +1 +1 Uncanny dodge (can't be flanked)
6 +6/+1 +5 +2 +2  
7 +7/+2 +5 +2 +2  Rage 3/day
8 +8/+3 +6 +2 +2  
9 +9/+4 +6 +3 +3  
10 +10/+5 +7 +3 +3 Rage 4/day, Uncanny dodge (+1 against traps), Cursed Reprieve

Weapon and Armor Proficiency:  A berserker is proficient with all simple and martial weapons, light armor, medium armor, and shields.  Note that armor check penalties for armor heavier than leather apply to the skills Balance, Climb, Escape Artist, Hide, Jump, Move Silently, Pick Pocket, and Tumble.  Also, Swim checks suffer a -1 penalty for every 5 pounds of armor and equipment carried.

Berserker Rage:  When he needs to, a berserker can fly into a screaming blood frenzy.  In a rage, a berserker gains phenomenal strength and durability but becomes reckless and less able to defend himself.  He temporarily gains a +8 to Strength, +8 to Constitution, and a +4 morale bonus on Will saves, but suffers a -4 penalty to AC.  Berserkers also have a supernatural ability while raging of Illusion.  The Illusion projected makes the berserker seem to grow 50% in size, as if under an Enlarge spell.  This effect is supernatural and most berserkers aren't even aware of it.  The illusion is divine in nature and goes away at the end of the rage.

The increase in Constitution increases the berserker's hit points by 4 points per level, but these hit points go away at the end of the rage when the Constitution score drops back to normal.  (These extra hit points are not lost first the way temporary hit points are; see temporary hit points, Player's Handbook page 129.)  While raging, a berserker cannot use skills or abilities that require patience and concentration, such as moving silently or casting spells.  (The only class skills he can't use while raging are Craft, Handle Animal, and Intuit Direction.)  He can use any feat he might have except for Expertise, item creation feats, metamagic feats, and Skill Focus (if its tied to a skill that requires patience or concentration).  A fit of rage lasts for a number of rounds equal to 3 + the character's (newly improved) Constitution modifier.  

The berserker may not prematurely end the rage voluntarily.  The rage must run its course and if there are no enemies around, the character must make a Will save (DC 15) or attack the nearest living creature.  If the character makes the save, he immediately passes out for 1d6 rounds.  When the character wakes, he suffers all penalties for the rage ending.  At the end of the rage, the berserker is fatigued (-4 to Strength, -2 to Dexterity, can't charge or run) for the duration of that encounter.  The berserker can only fly into a rage once per encounter, and only a certain number of times per day (determined by level).

Entering a rage takes no time itself, but the berserker can only do it during his action (see Initiative, Player's Handbook page 120), not in response to somebody else's action.  A berserker can't, for example, fly into a rage when struck down by an arrow in order to get the extra hit points from the increased Constitution, although the extra hit points would be of benefit if he had gone into a rage earlier in the round, before the arrow struck.

Some Berserkers are cursed, they go into a rage at the start of combat without willing the rage.  Cursed berserkers can go into a rage an additional number of times equal to their wisdom modifier.  These berserkers also gain a +10 to Strength instead of the normal strength bonus.  The time that a cursed berserker stays in the rage is also different.  A cursed berserker rages for a number of rounds equal to his newly improved Constitution modifier plus the results of a d10 roll.  The Will save to keep from attacking those around them is also increased to DC 20.  At the end of this rage, the berserker immediately passes out for 1d6 rounds.

Uncanny Dodge:  Starting at 2nd level, the berserker gains the extraordinary ability to react to danger before his senses would normally allow him to do so.  At 2nd level and above, he retains his Dexterity bonus to AC (if any) regardless of being caught flat-footed or struck by an invisible attacker.  (he still loses his Dexterity bonus to AC if immobilized.)

At 5th level, the berserker can no longer be flanked; he can react to opponents on opposite sides of him as easily as he can react to a single attacker.  This defense denies a rogue the ability to use a flank attack to sneak attack the barbarian.  The exception to this defense is that a rogue at least four levels higher than the barbarian can flank him (and thus sneak attack him).

At 10th level, the berserker gains an intuitive sense that alerts him to danger from traps, giving him a +1 bonus to Reflex saves made to avoid traps and a +1 dodge bonus to AC against attacks by traps.

Cursed Reprieve:  Upon attaining 10th level, a Cursed Berserker comes to grip with the demon within.  At this point, the Cursed Berserker can control when he enters into the berserker rage.  Due to the new control, the Cursed Berserker looses the extra times per day that he could rage.  He still retains the extra Strength bonus enjoyed by the berserker class, but he can now end his rages as if he was a normal berserker.  This ability doesn't effect normal berserkers

Ex-Berserker:  A berserker who becomes lawful loses the ability to rage and cannot gain more levels as a berserker.  He retains the uncanny dodge ability.  A cursed berserker who becomes lawful must make a Will save (DC 15) whenever he is in a stressful situation, (not just combat) or go into a berserker rage.  A cursed berserker who gains a level in another class also suffers the effects as if he had become lawful until he again gains a level in Berserker.