The Trill are a unique
joined species from the Alpha Quadrant composing of a vermiform symbiont
and a humanoid host. As a joined life-form, the Trill
enjoy a special relationship with past and future. The symbiont
lives many lifetimes with the benefit of remembrance, knowing
that in all likelihood they will survive beyond the lifetime of
any individual host.
The relationship between the Trill
symbiont and its humanoid host is complex. A joined Trill
integrates the personalities of the host and the symbiont, while
retaining memories and personalities of all the other hosts with
whom the symbiont joined with previously.
Coping with so many different
elements can be difficult. For this reason, host candidates are
screened very carefully as the host must must have a strong
desire to lead a full life and the will to pursue that life,
otherwise he or she takes the risk of being overwhelmed by the
symbiont's previous personalities.
Not all Trill are chosen to be
joined with a symbiont. Every year sees only five thousand
accepted into the initiate program and only about three hundred
accepted for joining. Hosts are seen as a link in the chain of a
symbiont's life; each link must be strong and unique.
The goal of a symbiont is to live
a rich and varied existence through their various hosts. Once
joined, the host and the symbiont become biologically
interdependent at which time non can really live for any amount
of time without the other. The resulting life form can be
considered to be an entirely different individual, although it
retains the memories of both life forms.