Odan Odan was a Trill symbiont in the 24th century . Odan was an accomplished ambassador for the and as of 2367 had been joined to at least three Trill hosts including , briefly , with a Human . ( ) History . In 2337 , Odan was joined with a male host . In this year , he mediated a dispute between the Alphan s and Betan s of the natives of Peliar Zel , whose government s had been in a rocky relationship since their moons were colonized . He worked with Lathal Bine ' s aunt and Kalin Trose . In 2367 , Odan had joined with a different male host and maintained that he was the previous host ' s son . He was tapped again to mediate a dispute with the Peliar Zel natives when the Alphans developed an energy source which disadvantaged the Betans . The Federation sent the to assist . It was hoped that he would be able to accomplish the same results this time and prevent a war between the two . During his efforts Odan refused transport to the surface and insisted on traveling by shuttlecraft . This led to an attack during which the host body was injured , necessitating the removal of Odan . Odan could not survive more than a few hours outside of a host . A was within range and with a suitable host aboard but the " Enterprise " could not leave Peliar Zel , and the transport was forty hours away . To extend the life of the symbiont , William T . Riker volunteered to become a temporary host . Odan was transferred to his body successfully , although he then had to spend some time convincing the moons ' ambassadors that he was still Odan despite his new appearance before negotiations could continue . Ultimately Odan was successful in averting a war , but barely in time to prevent permanent harm to the incompatible body of its host , Riker ; even before he was extracted , Odan rejected the offer of further immunosuppressant s despite the damage he was suffering in Riker because the drugs would have damaged Riker ' s body . With negotiations complete Odan was removed and joined to become Kareel Odan . The transfer of Odan had enormous repercussions . The two factions in the negotiations were initially skeptical of the explanation for Odan ' s change in appearance and negotiations almost never happened . At the same time , Odan and Doctor Beverly Crusher had begun a relationship prior to his host ' s injuries . The change in appearance proved professionally and personally difficult for Dr . Crusher ; although she had a romantic encounter with Odan while the symbiont was in Riker ' s body , she broke it off after Odan was transferred into Kareel , as it was too complicated to be involved with someone when they could change bodies so easily . Both of these reactions can be primarily attributed to the fact that the joined nature of the Trill was not widely known at the time . However , the extremely public and open display of such a surprising secret soon made the joined society of common knowledge . ( ) Appendices . Background information . Odan ' s male host was played by Franc Luz . Kareel , his new host , was played by Nicole Orth - Pallavicini . In contrast to the Trill later shown in " Star Trek " , where the host and the symbiont appear to share consciousnesses , Odan appeared to exert more control over his hosts , as he regularly referred to Riker as a body without any real sign that Riker himself had much impact on Odan ' s mannerisms or thoughts . However , this could be accounted for by the fact that Riker is the only Human seen being used as a host for a symbiont , creating the possibility that Odan had to suppress Riker ' s personality more than he would have done in a Trill host in order to gain the necessary control to complete his mission . Apocrypha . The difference between this symbiont and ones show later was explained in the non - canon novel " Forged in Fire " , which explained that the ridged Trill such as Odan ' s hosts were the result of a strain of the Klingon augment virus that managed to infect a Trill colony through visiting Klingon traders . However , the Trill seemed not to be interested in working on methods of restoring the original Trill look , with this ' sub - group ' having recently ( at the time the novel was set ) been re - accepted back into Trill society . The novel also revealed that Odan ' s disinclination to use transporters was simply part of a Trill policy to keep the symbiont ' s existence secret as the transporter scans would have picked it up ; presumably , after the public events of the negotiations Odan participated in while in Riker ' s body , this policy became less relevant , hence accounting for the ease with which Jadzia Dax transported . An earlier host of the Odan symbiont appears in Kristine Kathryn Rusch and Jill Sherwin ' s " The Lives of Dax " short story " First Steps " . Crusher encountered Kareel Odan again in the comics story " A House Divided " , when she acts as an advisor on the " Enterprise " - D as it is transporting a Trill master criminal to a new , high - security prison .