The Trill are a humanoid species based on the planet Trill in the Alpha Quadrant, in which a small percentage of the population harbors a sentient lifeform known as a symbiont inside their bodies, a symbiotic relationship that plays a significant role in Trill culture and society. Such "joined" Trill have personalities that are a synthesis of the two beings, and can access the memories and skills of previous hosts.

The physical process of being joined was irreversible. Once joined, the host and symbiont were dependent on each other after a ninety-three-hour period in which the symbiont bound itself to its host's nervous system. If the symbiont was removed from the host, symbiont and host would die within hours, even if they were otherwise healthy, unless they were implanted into another host or with another symbiont.

On average, only three hundred symbionts were available for hosting each year and about a thousand Trills apply for joining. Because of this, candidate Trill hosts had to undergo an extensive selection process to show eligibility and fitness before they could be matched to a symbiont.

Personality: Unlike Vulcans or Klingons, Trill do not really possess a stereotypical personality. As with Humans, their personalities span the spectrum. Like most other Federation members, they are generally optimistic, open to new ideas, and willing to help those in need.

Physical Description: Trill have the same average height and weight as Humans. Their skin tones range from pale pink to olive, but no darker; their hair, on the other hand, tends to be brown, black, or other dark shades. They have two rows of dark brown spots running from their foreheads down their bodies to their heels. Each Trill’s spots are as distinctive to him as fingerprints are to a Human.

Example Names: Trill place the given name before the family name. Joined Trill substitute the symbiont’s name for the family name. First names: Curzon, Joran, Tobin, Nilani, Emony, Ezri, Jadzia, Lenara. Symbiont names: Dax, Belar, Pren, Tigan, Otner.

Trill Species Traits

• +2 Intelligence. Trill receive a rigorous education to prepare them to receive a symbiont.

• Medium-sized: As Medium-size creatures, Trill have no special bonuses or penalties due to their size.

• Trill base speed is 30 feet.

• Skilled: All Trill undergo a rigorous training program to prepare them for joining. Like Humans, Trill receive 4 extra skill points at 1st level, and 1 extra skill point every level thereafter.

• Joining: Trill can join with a small, long-lived wormlike creature called a symbiont, thus becoming a symbiotic creature combining the knowledge and traits of both. All player character Trill are joined, or in some special circumstances (permission by GM) become joined during play. Roll 2d8 and divide by 2 (round down) for the symbiont’s number of past hosts. A joined Trill gains the following benefits:
  • To reflect their knowledge of the symbiont’s past hosts and their accomplishments, Trill gain a +2 species bonus to all Knowledge skill checks.
  • For each past host, you may select one trained skill and use it untrained.
  • For each past host, you can select one skill and it becomes a class skill. These skills are always treated as class skills.
  • Symbionts do not have feats independent of their host. Feats are and aspect of the host and do not carry over from host to host.
  • Some joined Trill cannot safely use transporters. To determine if this affects your character, roll 1d6; on a 1, the character suffers from this restriction. Every time the character uses a transporter, roll 1d6. On a 1 or 2, the character suffers 4d6+4 damage from the transport (no attack roll or saving throw applies)

• Automatic Language: Trill, Federation Standard.

• Level Adjusted +1.