when should multiple roles be listed in imdb credits

you're correct about how it's credits are shown (in the opening sequence) which is why I'm confident they were not listed with both "roles". In this particular case it's really wacky because they were themselves with their voice and simply delivered dialog as if they were another person. I use the term deliver in the context of giving lines as if they had lived another life. If you're not familiar with DS9 and Dax being a trill it's difficult to explain.There are shows where it's the same actor but they play an essentially duplicate person to themselves that is some how weaved into the story line.Contrast it with The Prestige for example where the same actor played two roles with heavy make-up. And if I'm not mistaken the credits I think listed both characters with the name. And I've done alot of cleaning on DS9 for duplicative info just like this. In this particular case what caught my eye is that only one actor has the trivia item when multiple actors did a "dual"role, so I have to wonder who loved Quark so much to make him special.

Just to illustrate what Phil G says, I copy/pasted this into the character field:John Smith/Post-man/Grocery Clerk (uncredited)/Jimmy Dune (uncredited)and got this, even after checking the "understood" boxes:

As I understand, it has to be done this way:Character: John Smith/Post-man/Grocery Clerk/Jimmy DuneAttribute: () () (uncredited) (uncredited)to have the result in Michelle's example.

That's certainly accepted by the contribution form. I don't have such an update, so I'm eager to get confirmation that it works when the characters are displayed.Is that documented in the guidelines?

Yes:https://help.imdb.com/article/contribution/filmography-credits/cast-acting-credits-guidelines/GH3JZC74FVYKKFMD#generalIf a cast member is listed more than once in the credits for playing multiple roles, list them once in the position of their first appearance (see cast orders), and separate the other roles in the character field with slashes, i.e., Role1/Role2/Role3 (This refers to the cast member's first appearance in the cast list rather than the appearance order of the multiple characters). Please do not put spaces either side of the slashes. If you notice that one of their multiple roles is missing or needs correcting, please submit your amendment with all the roles again, as above, separated by slashes. Do not submit the missing or corrected role on its own. If the same individual is credited twice under different names in the credits roll as well as playing separate characters you would need to add multiple (as) credits for each credited name in the attribute field in the order they appear e.g. (as Tim Smith) (as Timothy Smith).PS BTW: What if the first appearance was uncredited? ;)))

Phil G:Character: A/B/C Attribute: (credit only) (voice) (uncredited)

The above examples of mine are based on the official explanations. But now I also think, it may be not well explained because we can have a character with multiple attributes... So, it might be correct to explain this way:Character: A/B/C Attribute: (credit only)/(voice)/(uncredited)PS: I have no practical example at hand to try right now, sorry.PPS: I tried to simulate the (credit only)/(voice)/(uncredited) combination, but it does not work. So the system is not perfect for such cases.

 I found a case to try practical this variant:Character: A/B/C Attribute: (credit only/voice/uncredited)It also produces the result we don't need:A / B / C (credit only/voice/uncredited)Moreover, any use of attributes in the characters field this way:Character: A (credit only)/B (voice)/C (uncredited)Attribute: [empty]even if such would be allowed by system, is not possible for objective reasons. See for example the below mentioned Cloud Atlas (2012). Jim Sturgess plays different characters there, among them:Adam Ewing / ... / Adam (Zachry's Brother-in-Law)As we see, there is an objective reason to use the additional explanation (Zachry's Brother-in-Law) in credits, because there are two characters named 'Adam' both played by the same actor. So even if system allows, we could not use attributes in the characters field here :)))

Great thanks for clarification, Will!