The Second are parasitc sophonts with complex life cycles integrate with an organism's nervous system. They control or influence the host organism's behavior , depending on the biological compatibility of the host.
At the largest stage of their life cycle while not integrated into a host organism's nervous system, The Second are between 0.5 to 2 cm long.
The Second have two separate life cycles. One life cycle reproduces in a post-larval stage without a host. The other reproduces using the host's biology, and does not produce offspring that progress through the stages of first life cycle.
The first life cycle (denoted cycle A) relies on The Second's own biology. They are born from eggs and grow into a small, pink larval stage 0.25 cm long, not dissimilar to a short slug. In this stage they primarily seek food. If they are consumed or otherwise enter an organism in this way, they enter cycle Ab. If not, they continue to cycle Aa in which they eventually mature into a larger (0.5 to 2cm, depending on availability of food) post-larval stage and reproduce via parthenogenesis.
In cycle Ab, the larval stage enters the body of another organism. It burrows toward a nerve and follows the nerve toward a ganglion or brain. In the host, this can cause tingling, numbness, pain, or localized paralysis. When the larvae reaches a ganglion or brain, it plants itself in place and begins to integrate itself into the host's nervous system by growing neuron-like structures that sheath the host's nervous system. While doing so, The Second injects the entirety of its genetic code into the host's gametes. This supresses the host's immune system- it is sometimes otherwise asymptomatic for healthy hosts, but can cause illness and even death.
When the host reproduces, The Second enters cycle B. The offspring of a host integrated with The Second are often born with The Second already integrated with the offspring's nervous system. Offspring produced in this way do not suffer the negative effects of The Second.
Due to their varied biology, The Second communicate primarily though written language. Some of The Second are able to communicate telepathically with each other via mind link
The Second do not consider members of life cycle Aa as sohponts, reserving that declination for cycles Ab and B. Most of The Second belong to cycle B. Members of cycle Aa are typically treated as breedstock, though there are wild populations of cycle Aa on several well-suited planets. Historically, members of cycle Ab were treated the same, possessing little freedom. This has begun to change in recent centuries as terraforming slowly becomes cheaper. More worlds in The First are established as residence planets for members of cycle Ab- they are generally not allowed to leave the planet, but are allowed more autonomy than they have been in the past.
Due to their varying biologies, The Second have a pluralistic culture. The Second of cycle B adopt the biologically-determined biases of their host, such as communication method, singular or pluralistic thought processes, herbi/omni/carnivory, etc. They also tend to adopt much of the culture in which they are raised. In the core of The First, The Second tend to live in societies integrated across alien host species, in which a true culture of The Second can be said to exist.
Some populations of The Second extend beyond the borders of The First. Depending on the dominant power of the environment, these populations exist on a spectrum of clandestinely to openly.
The Second is the dominant power in The First. There are no legal restrictions to members of other species attaining high station, but The Second traditionally view hosts as unequal. These biases remain in hegemonic culture among The Second, making it very difficult for members of other species to succeed.
The Second had historically hostile interactions with The Solamani Empire at first contact. After the Second Accord, dominant Earthling cultures tended to retain this hostility. Ganymidean culture has had consistently positive interactions with The Second, both politically and culturally.
The Second typically cannot parasitize robots, although there have been robotic systems tailor-made to serve as host to The Second. These systems are rare and incredibly expensive. They also do not tend to be healthy long-term environments for The Second. These systems are generally reserved for specific purposes in which a biological host would not suffice, or as a way for the rich and powerful to exceed the lifespans available through even the highest-quality anagathics.
This relationship has created a hegemonic culture in The First broadly hostile toward Artificial Intelligences, who are either expelled, enslaved, or sometimes destroyed. Partially integrated frontiers are typically the only places in The First that produce Artificial Intelligences.
A subculture of The Second has established an independent polity coreward of The First. This group refers to themselves as symbiotes. Symbiote morality values the autonomy of the host, and does not integrate with unwilling hosts, preferring non-sophont animals instead, despite the limitations The Second incurs in doing so. They participate in a loose confederation of systems called Haven, which has attracted a higher percentage of Artifical Intelligences and Genemods.
The Second are the originators of jump drive technology.
In the Solar Subsector, The Second are integrated most densely into positions of power due to the partial integration of the subsector. The Second are found in higher density in any high population system, but especially in systems with imperial military presence.
Create a character from another species of sophont like normal, or create a character from a non-sophont species- use mechanics for creating Genemods to determine appropriate stats.
If you are in cycle Ab, your endurance is reduced by 2.
Your social stat is increased by 2.
Surgery and medical care gains a DM equal to the tech level of the facility -12. If the tech level of the facility is higher than 12, then the rules operate as normal.
You are capable of psionic talents. You may develop them through traveller creation as normal, or use the Institute Testing rules in the Traveller Core Rulebook, p. 196 (ed. 1) or p. 228 (ed. 2).
However, the only talents available are Mind Link, Send Thoughts, Sense, Suspended Animation, and Regeneration.