Breath Attack

Though most are similar to a cone attack, a breath attack has further additional rules that affect it:

Its maximum damage is generally determined by the user's HP. As the user's HP drops, its breath attacks get weaker.
Many breaths have a cap as to the amount of damage they can do when enemies use them to keep them from being too powerful (as monsters generally have far more HP than players do at higher levels). For instance, manticore's Heat Breath generally will not exceed 500 damage, and will not start doing less damage than that until the manticore reaches low levels of HP.
Its damage may be reduced by some other special means, such as standing further away from the user, or it may be reduced by standing away from the direct front of the user, etc.

While most breath attacks are cone frontal AoE, some are only single target, and some are even full radius AoE while still following the other standard rules of breath attacks. Pugil's Splash Breath and all Dragoon Wyvern breaths may only hit single targets, while a crab's Bubble Shower is radius AoE.

Certain equipment can reduce the damage taken from a breath attack. Many breath attacks also inflict a status ailment in addition to doing damage; the potency of this status ailment cannot be reduced by such equipment, nor will it vary by any of the above guidelines. Utilizing the appropriate Barspells, Carols, and resistance equipment can help in reducing the accuracy of said ailments.

Breath attacks generally ignore shadows but leave them intact.

Monster families with Breath Attacks

Enemies with "breath" attacks that inflict status effects but no direct damage have been omitted, as they are essentially undistinguishable from standard Cone Attacks.

Adamantoises (Aqua Breath/Earth Breath)

Crabs (Bubble Shower) (radius AoE instead of cone AoE)

Crawlers (Poison Breath/Incinerate)

Doomed (Acid Breath/Undead Mold)

Flies (Venom)

Funguars (Dark Spore/Silence Gas)

Hippogryphs (Choke Breath)

Hounds (Methane Breath/Poison Breath)

Leeches (Sand Breath)

Lizards (Plaguebreath)

Manticores (Heat Breath)

Morbols (Sweet Breath/Bad Breath)