Dax, DS9 1
Nothing like a good court martial episode to clear up what the unique characters are about early in a series. Like The Menagerie and Spock in TOS or The Measure of a Man and Data in TNG, Dax tries to explain all those niggling questions we have about Trills and Jadzia (and Curzon) Dax on DS9. Is a joined Trill responsible for what a Symbiote did with a previous host? Jeez, I don’t know. I can go either way on that. Luckily, this is one moral dillema we don’t have to deal with in the real world.