THE RISKADH IS A VERY, VERY FUN KLINGON SHIP TO PLAY.  Especially the later models, which have a decent balance of firepower and defensive oomph.  The styling of the FASA D-10 is also like that of the L-13 'Fat Man' in that this cruiser has a very slab-sided ST:TOS feel to it.  As always, this ship has no basis in official Trek canon and has never been seen in any movie or series as far as I know.  Its distinctive wedge-shaped wings would make it stand out on screen, so I don't think I've seen anything even remotely resembling the D-10 on any of the films or on any of the series.
        In FASA lore, this ship is quite storied, especially where the so-called 'Four Years War' is concerned.  In actual game use, this ship is a great match for the big Federation or Romulan cruisers; especially later models.  Packing a nice punch with powerful torpedoes and strong superstructure, I've had a lot of success with the D-10 ship over the years.  It's even more fun playing one or two Riskadh-class ships against a host of smaller, weaker opponents, because you have to think on your feet and use your potent weaponry wisely, otherwise you're liable to expend all your power chasing around the smaller ships while they slowly bleed you to death with phaser or disruptor attacks.
        In 2007 I tackled a re-draw project wherein I attempted to clean up the FASA graphics and reconcile the D-10's apparent size with that of the classic D-7 design.  The D-10, as it originally appears, has only two things in common with the D-7 K'tinga: the bridge pod, and the warp engines.  Because of its ubiquitous use in Klingon design, I opted to use the command pod as my scalar common reference, which actually blew up the D-10 quite a bit, in terms of its silhouette, when compared to the K'tinga.  This in itself posed a certain problem, in that the D-10, when re-sized, is approximately the same size as a Constitution Refit, which puts the D-10 well above the K'tinga in terms of mass.  Yet, the later model D-7 units and the D-10 units are all mass range X, according to the FASA mass chart; something not easily explained when the K'tinga is perhaps 2/3 the size of the Riskadh, and appears to possess not nearly as much secondary hull volume.  Add to this the fact that the dimensions as given by FASA place the D-10 and D-7 very close to one another, and it's difficult to determine which reference point, if any, can be trusted as accurate.
        In the end, I had to conclude that the later-model D-7 units were over mass, and that the D-10 was appropriately larger than expected; on the same order as the Constitution Refit, which is a mass XI vessel.  This would seem to be confirmed by the fact that, if we compare a correctly-sized K'tinga, Riskadh, and Constitution refit—all in a row—the D-10 is clearly on par with the Constitution Refit, both in terms of size, and also in terms of weaponry and other game stats.
        Surface detailing proved to be the final dilemma, in that the D-10 has traditionally employed the blank 'slab' aesthetic dating to TOS.  I experimented with some hull etching similar to the D-7, figuring the class could use some refined elements during a re-draw, but ultimately decided to keep the additional detailing to a minimum; no 'feathering' or other exoticness.  Thus, beyond scalar concerns, the new Riskadh still retains 90% of the original's overall look.

     — BRT

From the FASA Star Trek KLINGON SHIP RECOGNITION MANUAL, circa 1985
D-10 (Riskadh) Class VIII - X Cruiser
Known sphere Of Operation: Empire-wide use
Data Reliability: A for models A, D, and G; B for model F, D for model H.
Major Data Source: Models A, D, and G are in Star Fleet possession; Klingon Sector Intelligence
           On Stardate 1/9606, the D-10 cruiser, the design of which was strongly influenced by the D-7, was commissioned into service. The Klingon Imperial Command hoped to counter Star Fleet's Constitution class cruisers with this new vessel. The Four Years War was in its second year, and the Klingons had learned some of their lessons well. The D-10 featured a sturdy superstructure and the most effective shields the empire had to offer. The fore and aft-mounted disruptors were far superior to the Federation lasers, but were not as destructive as the Federation's accelerator cannons.
         The D-10 used the same command pod as the D-7, thus eliminating the need for additional production facilities. Like the D-7s pod, that of the D-10 is capable of being jettisoned and has similar sub-light maneuvering and life support capabilities. On Stardate 1/9802, Star Fleet captured a pod that had been jettisoned during the Battle of Kesse 16 months earlier; the crew were alive and as well as could be expected.
         The main hull of the early D-10s contain the engineering section, shuttlebays, crew quarters, and assault troop hypothermia capsules; later models have no troop-carrying capabilities but instead have large research facilities. The warp engines are mounted on short pylons and are jettisonable. With the additional removal of the hypothermia capsules, the ship is capable of running on its impulse power alone for up to one year. The shuttle hangars are located on the upper wing surface of the main hull and are seen as two large doors. Directly aft of these doors are located the aft firing disruptors; aft-firing photon torpedo tubes are located at the stern of the vessel just below the impulse exhaust port.
         The D-10 is the only Klingon warship whose class name honors a Klingon family line: the Riskadh line, which died with its founder, Kahless the Unforgettable, the greatest of all emperors. D-10s are manufactured at the Taamar, Gnuu Re', Fonawl, Z'hai, and Mustaka facilities. The combined production rate is 14 D-10Ds, 12 D-10Gs, and 10 D-10Hs per year.
         The D-10A first entered service on Stardate 1/9606, the first ships being rapidly sent into the Four Years War, where they proved to be the most powerful and feared ships in the Klingon Imperial Navy.
          The model used a powerful warp engine, but mounted a fairly weak impulse system, the only real shortcoming of the vessel; the main engines allowed the ships to cruise at Warp 6, with emergency speeds as high as Warp 8. The weapons system consisted of six individually-mounted KD-6 disruptors and two aft-mounted KD-3s, giving the cruiser an offensive range capability 80,000 km greater than Federation warships.
         With the Klingons having range superiority, if it had not been for the superior tactics of the Star Fleet commanders, the Four Years War might have turned out much differently. Star Fleet commanders were able to neutralize the range superiority in many cases, however. Klingon tactics were to send a D-10 with a small escort of three-to six destroyers into a system to secure it. Federation commanders would leave the system, making it appear unprotected; they would then return from several different directions and take the unsuspecting Klingons in flanking attacks. This tactic was not always successful, but it did deter the Klingons from mounting many attacks into the interior of Federation space. In the last months of the war, the Klingons faced the newly-developed phaser and photon torpedo, and the days of the D-10 as the "Queen Of Battle" were over.
          Of the 444 D-10As built, 27 are in reserve fleets, 268 have been converted to D models and 14 to F models, 106 have been destroyed, 8 have been captured (6 by Star Fleet and 2 by the Romulans), 6 are listed as missing, 7 have been scrapped, 6 have been sold to ranking families within the Empire, and 2 have been sold to private interests in the Triangle.
        The first modification to the D-10 came on Stardate 2/ 1012, when the KIB-2 impulse drive system was replaced with the KID-2. Though the new D-10B was ordered into production, it never was produced in numbers because the KWE-2 warp drive system was brought into the navy's inventory just as the new 8 models were ready for installation of their warp drives. These engines were installed, and, on Stardate 2/1201, the first D-10C was taken out for maneuver trials. On Stardate 6 2/1205, the completed ships were outfitted with the newly-created KD-9 disruptors, KP-4 photon torpedo, and the KSO shield systems, replacing the original equipment with upgraded systems. The D-10D entered service on Star- date 2/1307 with the simultaneous commissioning of 23 ships, the largest number of new ships to be commissioned at one time in known space.
         The KWE-2 warp drive system allows the D-10D to achieve cruising speeds of Warp 7 and emergency speeds of Warp 8, even though it adds 30,000 mt to the overall weight. The KD-9 disruptors produce slightly less damage than the KD-6 models found on the D-10A, but they have an increased range of 20,000 km. The real increase in weapons power lies in the KP-4 torpedo, which is mounted fore and aft. The addition of so many new systems required an in- crease in the superstructure strength.
         Of the 455 D-10Ds built, 389 remain in active service, 2 are used as training vessels, 47 have been destroyed, 2 have been captured by Star Fleet, 6 are listed as missing, 2 have been scrapped, I has been traded to the Romulans, 1 sold to the Orions, and 5 are in the service of ranking families of the Empire.
         During the years 2/1002 to 2/1410, the Klingons created 5 new warp drive engines, 2 impulse drive systems, 5 new disrupter types, 4 photon torpedo types, 5 shield systems (of which 2 used a trinary powertransformer),and 2 powerful computer systems. With all these new systems, the D-10F, incorporating many of them, was inevitable; it was commissioned on Stardate 2/1410. The KWE-3 engines produce 10% more power, and the KIE-1 impulse drive systems produce 50% more power than the systems installed on the D models, adding maneuverability. On Stardate 2/1312, the Klingons had acquired 14 Romulan plasma weapons of the RPL-1 type, and these weapons also were installed on the D-10F, instead of the photon torpedo. The KD-9 disruptors were replaced with KD-13s, increasing the range another 20,000 km, and the aft-firing KD-3s were replaced by 2 KD-9s and 2 KD-5s. The superstructure strength was increased by 16%, and the shields were upgraded.
         After the completion of the D-10F models, the Klingons continued to use the Z'hai facility to construct D-10Gs, with two changes from the F model. The hypothermia capsules were removed and the area rebuilt as a laboratory facility, allowing the D-10G to act as a research cruiser in hostile areas where lightly-armed ships like the D-9 could be easily destroyed or damaged if attacked while alone. To further augment weaponry, fore and aft-firing photon torpedo bays were installed for the KP-4 torpedo.
         On Stardate 2/2009, the D-10H was commissioned, the first model that has an exterior change. Instead of mounting the old style command pod, the ship mounted the command pod from the L-9 frigate, making the class easier to identify on visual scan but a more potent adversary. This model mounts the new KIE-2 impulse drive system, giving it more maneuvering power than most ships in either the Romulan Navy or Star Fleet. The disruptors were all refitted to KD-1 3s, not only to give the vessels a longer range of fire in all directions but also to ease the maintenance chore. The photon torpedo bay was converted to fire the new KP-6, which causes as much damage as any of those employed by Star Fleet and twice the damage as any used by the Romulans. With this array of weapons, and with its strengthened superstructure, the D-10H is, by far, the most powerful of the class and also stronger than most others in space.