Just because I can and I needed a little breather to get myself set for the next chapter I figured I would explain how the TIEs that Hades use got into business for those that don't know the story. For those that do, amuse a tired old writer. It should be noted that I do not claim this to be 100% accurate; it is based on my personal knowledge of the material from what I've read over the years. There may well be other versions of this development but this is the version I am applying for my story.
Prior to the Clone Wars Sienar Fleet Systems (then known as Republic Sienar Systems) developed a courier ship design for long range personnel transport (Darth Maul used a variant of this ship). Just before the Battle of Geonosis and the start of the Clone Wars Sienar began design of a starfighter based off this courier ship. This new fighter was dubbed the T.I.E. Fighter and was ready just in time for the war that followed and went into mass production for the newly formed Republic Navy which needed a cheap, mass production fighter to fill its ranks swiftly.
During the Clone Wars the T.I.E. served along other starfighters such as the Alpha-3 Nimbus V-wing and the Eta-2 Actis light interceptor. Sienar saw in these ships features that could be incorporated into the T.I.E. model and began designing an improved variant. When the Clone Wars ended and the Republic became the Empire and the subsequent Imperialization began Sienar was among the first to step up with a new fighter design that could replace the myriad of fighters formally used by the Republic. This was the TIE/In or TIE Fighter.
This new design was so successful that numerous variants were built, all on the basis of a small centrally located cockpit flanked by large solar panel wings. As the Empire grew in power these TIE/In based designs began to fall behind other starfighters being produced by other groups and Sienar was called upon yet again to further develop their design. The result was the TIE Advanced x1 (the starfighter was gifted to Lord Darth Vader as both a gift and a promotion for the fighter in the hopes that Vader's recommendation would lead to fleet service). This new fighter was worlds more powerful and capable than the prior TIE/In however it was far more expensive.
Because of this expense, only limited numbers of them were ever produced, however the research gained from their production resulted in the next stage of TIE development. The TIE/si or TIE Bomber and the new TIE/In or TIE Interceptor. Both of these designs proved satisfactory, the Bomber, much like the previous Fighter produced numerous variants around the time of the Battle of Yavin (boarding craft, shuttles, and other bomber types as well as a myriad of others) and the Interceptor entered fleet service just after the Death Star was destroyed; in time to take part in the follow up assaults on Yavin base and other Alliance facilities.
Sienar continued to improve upon what had turned into one of their greatest successes and continued to advance new models whenever possible resulting in dozens of TIE designs that saw varying levels of use. Eventually the TIE/ad or TIE Avenger was created, a further development of the original Advanced x1; once again it was deemed too expensive and like its predecessor saw very limited use in special or elite squadrons despite being a match for most other starfighters then in use. Sienar never stopped developing their design however and shortly after the Avenger was developed they once against released a new model.
This was the TIE/D or TIE Defender. A heavy starfighter designed to kill anything else that flew. These new starfighters surpassed everything Sienar had produced to that point and was arguably better than most of the starfighters in use by the Alliance to Restore the Republic (Rebel Alliance) as it was faster and more heavily armed than any prior TIE model. Once again Imperial doctrine got in the way, the Imperial tactic of throwing dozens if not hundreds of cheap fighters at an enemy was too heavily entrenched for this new fighter to gain any significant ground and like the Avenger it saw very limited use with special or elite units.
While the TIE Fighter, Interceptor, and Bomber and their variants continued to be the principal starfighters of the Imperial Fleet, ships like the Avenger and Defender became specialist starfighters, only in use by units like Hades or individuals who required a powerful transport. Even decades after the Empire's defeat at Endor the principal of the cheap disposable fighter held sway. The only advanced TIE design to ever see mass production on the scale of the Fighter, Interceptor, and Bomber was the Scimitar Assault Bomber.
There are literally dozens of TIE variants all having their roots in the original Star Courier design and later T.I.E Starfighter. In addition to the numerous Imperial models produced there are numerous non-Imperial designs such as the so called Uglies (composites of TIE and other starfighters) Zsinj's TIE Raptors, and Zaarin's TIE Experimental lines.