I'll give it a shot:
Bajor is militant, and controlled by the Holy Vedek Assembly. The Bajorans believe that Cardassia Prime's star system contains a holy portal that leads to the Prophets - and so they occupied Cardassia approximately 50 years ago. They aren't wrong - a few hundred years ago, a small fleet of Bajoran missionary warships accidentally entered the wormhole near Cardassia, and proceeded to convert a large portion of the Gamma Quadrant into the Holy Dominion. Starfleet will discover the wormhole soon after the start of our show....
Captain Worf, Task Force and Station Commander, Captain U.S.S. Valiant, Liberator of Cardassia Prime - Worf was put on a slightly faster track to command when Captain Picard was assimilated by the Borg. Riker became Captain of the Enterprise, Data became Exec, and Worf became Second Officer and was promoted to Lt. Cmdr at that point.* Admiral Picard later selected him for command of one of the new, small but powerful ships turned out by the Borg defense efforts, the Valiant**. A few years later, the Valiant was the made the lead ship in the task force assigned to liberate Cardassia Prime from the Holy Dominion of Bajor, and Worf was specifically tasked with preparing Cardassia's system defense afterward, and coordinating that defense with the Klingon Empire. Worf has made Devron Nor, a Cardassian space station previously controlled by Bajor, the task force base of operations.
Glinn Ziyal, First Officer and Cardassian Liason - the daughter of Legate Dukat, who is the head of the meager Cardassian Home Fleet***, and the Bajoran Tora Naprem, who was taken back to Bajor when the Bajorans were repulsed and put to death for supposed collaboration with the rebels. A bitter young woman who makes an extra effort to embrace all aspects of her Cardassian heritage, to prove herself Cardassian. She knows that some Bajorans are good - her mother proved that. But she hates their religion, and holds Emissary Kira personally responsible for her mother's death.
Lieutenant Cmdr. Julian Bashir, Task Force Operations Officer - part of a special group of "gifted individuals" that Starfleet regularly utilizes for strategic analysis, Bashir was assigned to the liberation task force to manage all of the operations needs of the combined Starfleet/Cardassian/Klingon defense group. A bit of an odd duck socially, Bashir is beginning to warm to Chief Engineer O'Brien, but seems more comfortable engaged in conversation with O'Brien's "companion", Lal.
Lieutenant Miles O'Brien, Chief Engineer, U.S.S. Valiant - When Valiant's previous Chief Engineer was transferred to be Chief on a larger vessel, Worf requested O'Brien, and Starfleet "mustanged" him to the rank of Lieutenant. This O'Brien and Keiko never clicked, but he did end up spending a lot of time with Lal, Data's "daughter", initially professionally, but ultimately on a personal level, as well. When O'Brien transferred to Valiant, Lal requested to accompany him, and Data approved, as he had grown concerned that his presence around her was limiting her growth. The exact nature of the relationship between the Chief and Lal is not clear to others around them. O'Brien fought against Cardassians that were serving the Bajoran religious nuts earlier in his career, but he is trying not to hold any of those experiences against the Cardassians now - they were subjugated then, after all.
Lieutenant Ezri Tigan, Security Officer, U.S.S. Valiant - Aside from being top of her class and excellent with shipboard weapons, young Ezri has yet to distinguish herself. She is in the Trill symbiote program, but unjoined as yet, and Lt. Dax has taken her under her wing.
Lieutenant Cmdr Eddington, Task Force Security Officer - Earlier in his career, he worked starbase security, but in the years before the liberation, Eddington was undercover on Cardassia Prime, gathering intelligence and coordinating with the rebels there. Upon his retrieval in preparation for sending the task force, he was placed in charge of coordinating security in the force.
Gul Damar, Head of Cardassian Home Fleet Security - Very similar in personality to the regular Damar, he is the last of our show's "Security Trinity". Occasional episodes are dedicated to Damar, Eddington, and Ezri working together to solve crimes in the task force, all CSI:TNG style.
Lieutenant Jadzia Dax, Starfleet liason to General Martok - This Dax's history is virtually identical to the one we know, and Worf and Martok find it useful to have her on Martok's flag bridge, both for her knowledge of Starfleet procedures, and her relative comfort working with Klingons.
Commander Ben Sisko, Captain U.S.S. Gallant, Second in Command of the Task Force - After his son was taken by the Borg during Wolf 359, Sisko entered a deep depression and took some leave time. Ultimately, though, his wife Jennifer was able to bring him out of his stupor and get him refocused. He went to Admiral Picard and joined the Borg defense efforts. Even though he knows it is incredibly unlikely, he hangs on Picard's example a hope that one day, he and his wife will recover their son. He seems very driven in the current mission - perhaps too much so - but makes no bones about being eager for Starfleet to put together a mission to take fighting to the Borg. The Gallant is the ship in the Task Force most often sent for 'away' missions.
Emissary Kira Nerys, Holy Vedek of the Prophets - Once the personal representative of the Holy Vedek Assembly on Cardassia, Nerys still hopes to find a way to retake the system, although she knows that with the Klingons and Starfleet present, it will require more intelligence than force. But the Prophets will lead the way somehow....
Odoun - Although to all outside appearances he is a Vorta, one of the attendent species of the Holy Dominion, he is actually a member of a race of shapeshifters native to the Gamma Quadrant. The shapeshifters are determined to overthrow the Dominion, or, at the very least, mitigate the effects of their tyranny where possible. Odoun has managed to take the place of the personal assistant to Emissary Kira.
DaiMon Quark of the Ferengi Alliance - A recent arrival to Devron Nor, DaiMon Quark is interested in setting up a shop as an embassy and base of operations in what may now prove to be an excellent market, with the Bajoran religious prescriptions out of the way. Worf allows this, both because it is better to have a black market you know than one you don't, and because if the Bajorans attack they would then risk offending the Ferengi Alliance, as well, and bringing them into the conflict.
Garak - A tailor on the main promenade of Devron Nor, he may have been involved in the rebellion against the Bajorans. It is also possible that he was a collaborator and informant for the Bajorans. It is actually likely that both of these were true as it served Garak's own purposes.
* (Captain Picard was recovered from the Borg, but decided to accept a promotion to Admiral to oversee Borg defense projects and make himself accessible to Starfleet Command due to his intimate relationship with the Borg, and to pursue "the road not taken" with Dr. Crusher. Commander Shelby went with him.)
** Valiant-Class starships are small enough to be commanded by a Commander, or in some cases, even a Lt.Cmdr.
*** The CHF consists of Bajoran ships that had majority-Cardassian crews and thus turned on the Bajorans during the liberation.
Bajor is militant, and controlled by the Holy Vedek Assembly. The Bajorans believe that Cardassia Prime's star system contains a holy portal that leads to the Prophets - and so they occupied Cardassia approximately 50 years ago. They aren't wrong - a few hundred years ago, a small fleet of Bajoran missionary warships accidentally entered the wormhole near Cardassia, and proceeded to convert a large portion of the Gamma Quadrant into the Holy Dominion. Starfleet will discover the wormhole soon after the start of our show....
Captain Worf, Task Force and Station Commander, Captain U.S.S. Valiant, Liberator of Cardassia Prime - Worf was put on a slightly faster track to command when Captain Picard was assimilated by the Borg. Riker became Captain of the Enterprise, Data became Exec, and Worf became Second Officer and was promoted to Lt. Cmdr at that point.* Admiral Picard later selected him for command of one of the new, small but powerful ships turned out by the Borg defense efforts, the Valiant**. A few years later, the Valiant was the made the lead ship in the task force assigned to liberate Cardassia Prime from the Holy Dominion of Bajor, and Worf was specifically tasked with preparing Cardassia's system defense afterward, and coordinating that defense with the Klingon Empire. Worf has made Devron Nor, a Cardassian space station previously controlled by Bajor, the task force base of operations.
Glinn Ziyal, First Officer and Cardassian Liason - the daughter of Legate Dukat, who is the head of the meager Cardassian Home Fleet***, and the Bajoran Tora Naprem, who was taken back to Bajor when the Bajorans were repulsed and put to death for supposed collaboration with the rebels. A bitter young woman who makes an extra effort to embrace all aspects of her Cardassian heritage, to prove herself Cardassian. She knows that some Bajorans are good - her mother proved that. But she hates their religion, and holds Emissary Kira personally responsible for her mother's death.
Lieutenant Cmdr. Julian Bashir, Task Force Operations Officer - part of a special group of "gifted individuals" that Starfleet regularly utilizes for strategic analysis, Bashir was assigned to the liberation task force to manage all of the operations needs of the combined Starfleet/Cardassian/Klingon defense group. A bit of an odd duck socially, Bashir is beginning to warm to Chief Engineer O'Brien, but seems more comfortable engaged in conversation with O'Brien's "companion", Lal.
Lieutenant Miles O'Brien, Chief Engineer, U.S.S. Valiant - When Valiant's previous Chief Engineer was transferred to be Chief on a larger vessel, Worf requested O'Brien, and Starfleet "mustanged" him to the rank of Lieutenant. This O'Brien and Keiko never clicked, but he did end up spending a lot of time with Lal, Data's "daughter", initially professionally, but ultimately on a personal level, as well. When O'Brien transferred to Valiant, Lal requested to accompany him, and Data approved, as he had grown concerned that his presence around her was limiting her growth. The exact nature of the relationship between the Chief and Lal is not clear to others around them. O'Brien fought against Cardassians that were serving the Bajoran religious nuts earlier in his career, but he is trying not to hold any of those experiences against the Cardassians now - they were subjugated then, after all.
Lieutenant Ezri Tigan, Security Officer, U.S.S. Valiant - Aside from being top of her class and excellent with shipboard weapons, young Ezri has yet to distinguish herself. She is in the Trill symbiote program, but unjoined as yet, and Lt. Dax has taken her under her wing.
Lieutenant Cmdr Eddington, Task Force Security Officer - Earlier in his career, he worked starbase security, but in the years before the liberation, Eddington was undercover on Cardassia Prime, gathering intelligence and coordinating with the rebels there. Upon his retrieval in preparation for sending the task force, he was placed in charge of coordinating security in the force.
Gul Damar, Head of Cardassian Home Fleet Security - Very similar in personality to the regular Damar, he is the last of our show's "Security Trinity". Occasional episodes are dedicated to Damar, Eddington, and Ezri working together to solve crimes in the task force, all CSI:TNG style.
Lieutenant Jadzia Dax, Starfleet liason to General Martok - This Dax's history is virtually identical to the one we know, and Worf and Martok find it useful to have her on Martok's flag bridge, both for her knowledge of Starfleet procedures, and her relative comfort working with Klingons.
Commander Ben Sisko, Captain U.S.S. Gallant, Second in Command of the Task Force - After his son was taken by the Borg during Wolf 359, Sisko entered a deep depression and took some leave time. Ultimately, though, his wife Jennifer was able to bring him out of his stupor and get him refocused. He went to Admiral Picard and joined the Borg defense efforts. Even though he knows it is incredibly unlikely, he hangs on Picard's example a hope that one day, he and his wife will recover their son. He seems very driven in the current mission - perhaps too much so - but makes no bones about being eager for Starfleet to put together a mission to take fighting to the Borg. The Gallant is the ship in the Task Force most often sent for 'away' missions.
Emissary Kira Nerys, Holy Vedek of the Prophets - Once the personal representative of the Holy Vedek Assembly on Cardassia, Nerys still hopes to find a way to retake the system, although she knows that with the Klingons and Starfleet present, it will require more intelligence than force. But the Prophets will lead the way somehow....
Odoun - Although to all outside appearances he is a Vorta, one of the attendent species of the Holy Dominion, he is actually a member of a race of shapeshifters native to the Gamma Quadrant. The shapeshifters are determined to overthrow the Dominion, or, at the very least, mitigate the effects of their tyranny where possible. Odoun has managed to take the place of the personal assistant to Emissary Kira.
DaiMon Quark of the Ferengi Alliance - A recent arrival to Devron Nor, DaiMon Quark is interested in setting up a shop as an embassy and base of operations in what may now prove to be an excellent market, with the Bajoran religious prescriptions out of the way. Worf allows this, both because it is better to have a black market you know than one you don't, and because if the Bajorans attack they would then risk offending the Ferengi Alliance, as well, and bringing them into the conflict.
Garak - A tailor on the main promenade of Devron Nor, he may have been involved in the rebellion against the Bajorans. It is also possible that he was a collaborator and informant for the Bajorans. It is actually likely that both of these were true as it served Garak's own purposes.
* (Captain Picard was recovered from the Borg, but decided to accept a promotion to Admiral to oversee Borg defense projects and make himself accessible to Starfleet Command due to his intimate relationship with the Borg, and to pursue "the road not taken" with Dr. Crusher. Commander Shelby went with him.)
** Valiant-Class starships are small enough to be commanded by a Commander, or in some cases, even a Lt.Cmdr.
*** The CHF consists of Bajoran ships that had majority-Cardassian crews and thus turned on the Bajorans during the liberation.
