Ketsu Onyo's star ship, the "Shadow Caster", is a reuse of a vehicle that was created for Star Wars: The Clone Wars but was never seen on screen. It was originally supposed to be Asajj Ventress' ship, "The Banshee", which would have featured in an unfinished story arc that was adapted into the 2015 novel "Dark Disciple". Pablo Hidalgo suggested the name "Shadow Caster" because that was the name of the ship he used in his Star Wars role playing campaigns when he was a teenager.
Ketsu Onyo's look is based on early unused concept art created for Star Wars: Episode VII - The Force Awakens (2015).
The two shuttles in Bay 22 at the beginning of the story have the word 'Spacebus' written on either side in Aurebesh lettering. At first only their right, or starboard, sides are shown, on which the letters are mirrored and therefore spelled backwards. Later, when one of the shuttles is in flight, you can see the word in regular Aurebesh on its left, or port, side.
The Aurebesh text on the green viewscreen seen on the bridge of the Imperial Star Destroyer translates to "Incoming Transmission".