This special quality makes a creature’s very presence unsettling to foes. Activating this ability is a free action that is usually part of an attack or charge. Opponents within range who witness the action may become frightened or shaken. The range is usually 30 feet, and the duration is usually 5d6 rounds. This ability affects only opponents with fewer Hit Dice than the creature has. An opponent can resist the effects with a successful Will save (DC 10 + 1/2 the frightful creature’s racial HD + the frightful creature’s Cha modifier; the exact DC is given in the creature’s descriptive text). An opponent that succeeds on the saving throw is immune to that same creature’s frightful presence for 24 hours. On a failed save, the opponent is shaken, or panicked if it has 4 Hit Dice or fewer. Frightful presence is a mind-affecting fear effect.

Format: frightful presence (60 ft., DC 21); Location: Aura.

Spells, magic items, and certain monsters can affect characters with fear. In most cases, the character makes a Will saving throw to resist this effect, and a failed roll means that the character is shaken, frightened, or panicked.

Shaken: Characters who are shaken take a –2 penalty on attack rolls, saving throws, skill checks, and ability checks.

Frightened: Characters who are frightened are shaken, and in addition they flee from the source of their fear as quickly as they can. They can choose the paths of their flight. Other than that stipulation, once they are out of sight (or hearing) of the source of their fear, they can act as they want. If the duration of their fear continues, however, characters can be forced to flee if the source of their fear presents itself again. Characters unable to flee can fight (though they are still shaken).

Panicked: Characters who are panicked are shaken, and they run away from the source of their fear as quickly as they can, dropping whatever they are holding. Other than running away from the source, their paths are random. They flee from all other dangers that confront them rather than facing those dangers. Once they are out of sight (or hearing) of any source of danger, they can act as they want. Panicked characters cower if they are prevented from fleeing.

Becoming Even More Fearful: Fear effects are cumulative. A shaken character who is made shaken again becomes frightened, and a shaken character who is made frightened becomes panicked instead. A frightened character who is made shaken or frightened becomes panicked instead.

Several special immunities are granted while you have 50% or more of your current max HP:
You can't be compelled to forfeit or commit suicide.
Auto-kill effects (such as quivering palm or circle of death) deal 1d6 damage per CL/HD instead of auto-killing on a failed save (plus whatever they do on a passed save).
Ability/level damage/drain can't drop a score/level below 1.
While affected by a disabling effect, you roll another saving throw every round at the end of your turn to determine if you are affected for another round (think Hold Person). A single success ends the effect. A "disabling" effect is anything that causes the target to be unable to take their normal actions (confused, dazed, dominated, frightened, nauseated, paralyzed, staggered, stunned, panicked, unconscious). A successful saving throw ends the effect but doesn't stop you from being affected again by the same effect later nor does it heal damage taken from the effect (unless noted otherwise). If the effect already grants a saving throw to end every round, this doesn't stack with it (take whichever is better).
*You do not gain these immunities against foes with a CR that's 4 or more points above yours.
*Arena Immunities can be turned OFF in PvP matches if all players agree to it.
*Accumulating nonlethal damage effectively lowers your HP for these calculation purposes.