Inspired by the Bolo series of books
https://en.wikipedia.org/wiki/Bolo_universe, and this original story
https://forums.spacebattles.com/threads/the-last-angel.244209/ the PC has found an ancient Sith Harrower class dreadnought, "Dread our Wrath" created by a powerful sith lord/engineer in the Great Galactic War of SWTOR from pieces of rakatan technology.
"Onslaught Omega", The AI of the "Dread our Wrath," has 7 levels of soldier and 3 of elite trooper (recently fully unlocked) and can enter a hyper heuristic mode (from Bolo) where the AI and PC's brain interface and can make high accuracy attacks. It also has extremely high levels of automation and does not require a crew.
The origin for this was the PC was digging through the Hoth ship graveyard for loot to fund a new rebellion against the Imperial rule.
https://starwars.fandom.com/wiki/Starship_Graveyard_(Hoth)I created a excel spreadsheet to randomly determine (1) which ships were there, and in (2) what condition. There was a harrower dreadnought that 100% intact, and I got thinking of how on earth that possibly could have happened.
So I thought in typical Sith fashion, some of them used the Battle of Hoth as a cover to settle scores with rivals. The creator of the ship and her acolytes were tricked into using their cryo stasis chambers to survive serious "battle damage." (Note, there's been a whole plot arc about the PC finding these same people all still alive, in the stasis fields, and avoided dealing with the problem (i.e. Does he just murder them while they're helpless in cold blood? Or does he wake them up and let them out? - Eventually they did wake up during a ship battle when the Dread our Wrath took serious battle damage. Now most of them have escaped and are going to come back and cause problems for the PC later.)
Anyways - what actually happened was the PC faced down 3
already damaged ISD's, as they had been going through the Cron Drift for a year to chase down Jedi fleeing to Ossus. The Dread Our Wrath took them on to protect the planet and the Jedi Temple + refugees. After disabling the ISD's, the PC sent a message to the ISD's to abandon ship or be destroyed, and made an excellent intimidation roll.
The Dread Our Wrath has tractor beams to tow these ISD's. I've also introduced some complications using these, as they are in general meant for short term use (i.e. battle, or incidental use) and were highly experimental for the time they were built. (3670 BBY) As such, using them for tugboat operations means they face increased strain, and may rupture and need repairing.