Rogues? Techically a player-controlled adventurer is a rogue (and it is, after all, a rogue-like we are playing!) and subscribes to as much or as little of the behaviours that NPCs are hard-coded to as the player him/herself decides, for the most part.
Whilst this
needn't be an omnicidal maniac, dealing death upon any or every living being they think they can get away with attcking, the Adventurer is certainly capable of being amorally aloof and unconcerned by basic.cameraderie with peers, etc...
OTOH, reserve 'Rogue' to a future appearance of another player's Adventurer invegling their way into you active fortress, mid-play, in some mythical multiplayer and mixed-mode capable release. Player A's adventurer just needs to tag along behind some migrants found migrating across the landscape, effects a disguise as suitable to be one of them and then, on entering the fortress, starts receiving 'compulsions' or orders from the fortress's 'controlling entity', which he or she
need not follow, but might at least feign to some degree whilst scoping out the fortress and learning its secrets and pocketing its artefacts and maybe occasionally bumping (otherwise) solitary dwarves off when the hope is that the fortress controller isn't viewing that precise location..
Well, just an off(/over) the wall idea... That isn't even in the far-future-of-the-fortress official leaning...