Sentry (caste)

* Standard
* Domed

## Sentry

The **Sentry** is the typical quadrupedal adult form of the Xenomorph XX121 species and is designated as a Stage 4 Xenomorph life form. Unlike the standard Warrior, the Sentries are the main defensive unit of the hive and appear to be the most numerous quadrupedal caste of any hive. Their main duty is protecting weaker siblings in the hive, such as the Drone or Worker. They molt from Runners and possess the same speed and agility as their infant counterparts.

## Characteristics

Much like the distinction between Drones and Warriors, Sentries are separated from Runners by their hard ridged carapaces, though this is not always the easiest way to distinguish them. What does easily distinguish them, however, is the newly formed dorsal spines that the Sentry develops. Their tail blade doesn't change much but does become more serrated and thicker. Some Sentries develop blade-like structures on their elbows.

Much like Warriors, the average sentry loses its ability to spit acid and is much less cautious than the Runner, not afraid of throwing themselves at heavily armed enemies. Naturally, they are much more robust than the weaker Runner and will relentlessly defend the hive to their deaths.

While known to employ ambush tactics and stealth, the Sentries tend to prefer head-on assaults and use large numbers to overwhelm their opponents much like Warriors. Though solitary Sentries have been observed, this is not the norm. They are much stronger than their Runner counterparts and use this strength to their advantage when hunting prey. They also seem to be smarter than the Runners, who are usually more instinctual like their hosts.

A unique trait of the Sentry is that it develops specialized hands and feet that are adept at gripping, scaling, and climbing, more so than other Xenomorphs. This combined with their extreme speed and reflexes makes the Sentries an extremely adaptable and formidable force.

## Variants

The Sentry Xenomorph has a wide range of structural variations and mutations, listed below are the known unique variants of the Sentry.

### Cystic enhanced

Sentries born from hosts infused Cystic Acid are enhanced in their strength and resilience. These variants of the Sentry are denoted by a crimson stripe down their carapace. Any of the other variants of the Sentry have the potential to also be Cystic enhanced.

### Sentry Domed

Often confused for a Runner at first glance, the Sentry Domed variant are immature Sentries who have yet to shed their domed carapace. The dome becomes much darker and more opaque as it becomes more rigid with age, eventually shattering and revealing the ridged head underneath.

### Sentry Carved

While already possessing a ridged carapace, the variant known as Sentry Carved possesses a much more rugged carapace and overall look. Their carved, ridged head gives them additional ballistic resistance over the standard Sentry.

### Evolved Sentry

Similar to the Evolved Warriors, these Sentries will mutate when a hive grows in size into their own unique type. Highly adaptable, these creatures are often mistaken for a standard Sentry until it is too late for their enemies. Some of them are able to spray acid at close range onto multiple enemies at once, others can camouflage their mesoskeleton to blend into their surroundings to leap upon their foes, and some of them are even able to heal the most grievous of wounds almost instantly.

These Evolved Sentries, also known as Lucky Dip Aliens, are slightly larger than their standard counterparts and only have one pair of dominant dorsal spines with the other pair short and stubby. They are believed to be an evolutionary dead-end and once their metamorphosis has finished, it will change no more after that. It is theorized that their evolution is due to an immediate need that the hive requires, but not as a long term creation. Each one is different and there is no way to determine what capabilities it has until it has displayed them.

### Virulent

A Sentry that has molted from a Virulent Runner will possess the same subcutaneous stinger-tipped venom sacs that inject high concentrations of toxic spores that multiply in sufficient quantity to turn bodily fluids black and soupy, sickening and nauseating the host organism in the process. The Virulent strain is not capable of developing on its own and must molt from a Virulent Runner.

### Onslaught Genome

Much like the regular Warrior, Sentries possess the dormant Onslaught Genome that when activated by a Queen's pheromones, will allow them to evolve to become more suitable for heavy assaults. They become physically stronger and extremely ballistic resistant, as well as greatly improving their regenerative capabilities to the point that they can completely regenerate lost limbs. It is possible the Onslaught Genome has some connection to the Evolved Sentries.

## Evolution

Much like their wide variations in structure and purpose, the Sentries also have great evolutionary potential. Their evolutions branch out into various hive roles and can even molt into the beginnings of a Queen. Below are the known evolutions of the Sentry.

* Boiler — An old and diseased kamikaze mutation of the Sentry.
* Burrower — A support caste for assisting in the creation of hives.
* Crusher — A Stage 5 heavy assault caste, built to defend hives.
* ??? — A heavy assault caste, built to combat armored vehicles.
* Royal Guard — A young Praetorian and the first step towards a Queen.