A Trill ambassador and mediator whose relationship with Beverly Crusher revealed the nature of the joined Trill to the Federation.
Odan was a Trill diplomat who came aboard the Enterprise-D in The Host to mediate a dispute between two moons of Peliar Zel. He and Beverly Crusher fell in love. When his shuttle was attacked and his host body fatally injured, it was revealed that Odan was a symbiont living inside a humanoid host.
Until a new host could arrive, the symbiont was placed temporarily in William Riker, allowing Odan to complete the negotiations and continue the romance. The new host turned out to be a woman named Kareel, and Beverly felt unable to continue the relationship.