The Four Horses of the Apocalypse

It's no secret that many of the human myths and legends come from interactions with the spirit world. One such legend pertains to the Four Horsemen of the Apocalypse.

What few people know is that the horsemen themselves were significantly less pertinent than their mounts. These creatures, though similar to Hollows in appearance and general abilities, lack the distinctive holes that mark Hollows. Further, they seem uncapable of being purified via Konsou, and do not possess the ability to transform themselves (except when ridden).

Though sharing the characteristics of their myth-like counterparts, the horses are not themselves linked to the end of the world. Instead, they are intelligent beasts native to Hueco Mundo, supposedly not born of the cycle of Reincarnation, of nature unknown (arguably the embodiment of their respective aspects). They cannot be permanently killed, though they CAN be disabled; usually, they will reform in a matter of days in a location of Hueco Mundo after they are defeated, except when they test their would-be riders (in which case they surrender before the final blow).

Anyone can try and tame these dangerous creatures. The most common method is direct combat.

The mount that least resembles an actual horse. Its mane is leonine, and its mouth opens wide in jagged, sharp teeth. Its hooves end in massive claws, and between the plates of its Hollow exterior burst occasional flames, which run along its body to form a tail. Instead of eyes, it has burning embers.

Abilities: War incites bloodlust in all creatures near it, as well as increasing temperature by several degrees. Plantlife usually burns in its presence. It grants a significant increase to its rider's attack powers (increased Cero/Bala/Kidou/Zanpakutou strength), at the cost of a decrease in their defensive capabilities and tactical thinking (think Berserkers, including how they seem to ignore pain). War is capable of Cero and Bala, with the former being incredibly destructive with a large radius - visually, like a massive, intense fireball. It has poor Hierro, however, and only average Sonido. Fusion with its rider (through Shikai/Bankai/Ressurreccion/Segunda Etapa) grants him or her the ability to manipulate fire, as well as the capabilities already described (which intensify even more).

Pestilence looks like a bloated horse that breathes noxious fumes. Its coat is a sickly, discolored green between its plates, and unlike the other mounts, it has actual, physical eyes which look blinded as though from cataracts, with slimy green tears running the sides of its horrid face. Somewhat resembles a zombie horse, except the flesh is evenly decayed.

Abilities: Pestilence poisons the air around it. The poison acts both when inhaled and in contact with the skin, causing nausea, irritation of the eyes and nose, a nasty cough, and rashes. Prolonged exposure causes the flesh to rot. Its effects are proportional to the victim's Reiatsu - the stronger the victim, the more slowly it works. Its rider is not immune to its effects, though it works at a significantly slowed rate. It has subpar Cero, though its Bala have a dangerous corrosive effect that weakens the target's defenses (and immune system in case of a direct hit). It has great Hierro and subpar Sonido. Fusion with its rider grants him/her the ability to corrode their enemy with its attacks. It saps at his/her stamina at a greater rate than usual, however.

Famine is the sleekiest of the four horses. It seems almost literally skin and bone, and it's smaller than the other three mounts. Its tail is made of bone, and its eyes burn a cold blue. Its coat is bright blue, as well.

Abilities: Famine feeds on blood and Reishi. It continually absorbs the ambient Reishi as well as any Reiryoku that happens to come its way. As a result, energy-based attacks have a diminished effect on it (low-grade attacks are completely ignored). If any target happens to be drained completely of Reiryoku, it begins to slowly sap its vital strength as well, as the target visibly withers. Its Cero and Bala are both significantly weak, at least until it feeds. It has very poor Hierro, but is the fastest of the four horses as far as Sonido goes. Fusion with its Rider makes him/her capable of draining Reiatsu with each attack, replenishing their own reserves, as well as regenerating if they draw blood (with the amount of regeneration being proportional to the blood drawn). Famine is impossible to satisfy, and is the hardest horse to control - the more it consumes, the hungrier and thirstier it becomes, potentially turning on its rider if it runs out of sustenance.

The most magnificent of the horses, though it seems quite plain in comparison to their grotesque appearance. Its mane, tail and eyes resemble the starred skies in a bleak, moonless night. Its coat is of a white so pale as to be almost translucent, giving it a ghostly appearance.

Abilities: Death radiates its namesake. The weakest creatures and plantlife instantly wither and die in its presence; humans fall to the ground as though their bodies simply stopped. Creatures killed in this manner can be reanimated and made to fight by Death itself. (Its defeat causes the control to vanish; if the creature in question didn't sustain any life-threatening wounds, then it may be ressuscitated through normal means such as CPR.) Death can also control the skeletons and bodies of creatures killed by other means. Though the creatures themselves are not particularly potent, they cannot be permanently killed so long as Death is around. Mere unconsciousness suffices for it to establish control, though the body is significantly less capable under such circunstances.
Gazing into Death's eyes induces despair. It uses the deepest insecurities and fears of the target against itself, causing it to hallucinate in the back of its mind and inciting fear. The target may not understand why, but it becomes increasingly more frightened with the passing of time. Sufficiently iron-willed targets may overcome or compensate for its effects.
Death's Cero does not detonate, instead creating a small orb of nothingness that sucks everything into it. It grows as it absorbs things, though a significant blast of energy (or harming Death itself) can dissipate it. Its Bala induces temporary numbness and, with sufficient impact, localized paralysis. It has average Hierro and Sonido. Fusion with its Rider grants him/her its natural abilities, plus the ability to create vaccuum with its attacks, drawing them closer.