Annihilation was set right after the SWTOR class events in the game and before/during the events on Ilum as Darth Malgus began his move against the Dark Council. The novel began with Satele Shan struggling with the birth of her secret child and the separation that was forced due to her allegiance to the Jedi Order. Theron was raised by Jedi Master Ngani Zho to be his padawan until it was obvious that Theron wasn't a force sensitive. Theron left only to serve the Republic as a SIS Agent and through the course of the novel, he was instrumental in an operation to destroy an Imperial war machine that could turn the tide of war. 
 I am a Star Wars The Old Republic player for a couple of years now and I knew Theron Shan from the game. Having him as a Republic agent who was willing to form an alliance in Shadow of Revan, then in Rise of the Emperor in which he was involved in a failed mission on Ziost and the conclusion left him emotionally distraught and his disenchantment with the republic grew and as the former Republic spymaster in Knights of the Fallen Empire and Knights of the Eternal Throne. I haven't care enough to romance him but I love him just the same. 
 I'd admit it took a couple of years for me to read from the start until end of this novel. I have read a couple of Karpyshyn works on Mass Effect and I knew Star Wars is his dominion. But this novel wasn't as tightly written as Mass Effect Ascension. In fact, I speed read through a lot of pages whenever I feel descriptions and characters doesn't feel like it add anything to the main narrative. 
 However, what save this book was the fact that the family subplot that made me invested. Through the course of the story, you are also being introduced with Jace Malcolm, the Supreme Commander of the Galactic Republic and formerly the leader of Havoc Squad and a famous Republic war hero, who found out that he have an adult son after receiving the mission report of Theron's involvement on Nar Shadda's failed operation. Knowing that he had lost decades of missing out on his son's life, he struggled with his desire to get to know Theron better and also his feelings for Satele Shan with whom he still maintain in contact with throughout the decades at a professional capacity. For Satele, the novel explored part of herself as the Jedi Grandmaster of the Jedi Order who have to uphold her vows to protect the Republic and also as an emotional character who still struggled with the forbidden love she have for her son and her son's father. 
 Despite myself enjoying much of his dare-defying actions but I don't feel Theron was that well-fleshed as a character. Sure, he is a lot younger and less matured than the person I knew. He still have all the roguish qualities; recklessness, unpredictability, resourceful and he still making up as he goes but at times he felt bland and uncharismatic and often fluttered through pages being a badass hero or a helpful sidekick. 
 I think it was largely due to multiple narratives that felt somewhat disjointed especially since this novel is quite short. Personally, it could have work better with limited POVs with just several key characters; Theron, Darth Kharrid, Jace and Satele. Gnost-Dural seems so much more awesome as a periphery character than as a narrator. I'm aware that she is an established comic character but I couldn't even care about Teff'ith, to me she's just a Mission Vao/Vette/Liara substitute who serve as a convenient plot device which I wished the writer could stop doing this to all of his young female characters creations. 
 Either way, if you're already a Star Wars fan who read any novels that have Star Wars name on it, the novel is well-written than most SW EU novels that I've read. If you're a SWTOR player, you might find some continuity with the current storyline. If you're a hopeless romantic as me, reading Satele's part with Jennifer Hale's voice and her broken romance with Malcolm and some of his observation of her... kinda mirror my Shepard and Kaidan for a bit. Fortunately, there's a light at the end of that tunnel with this older pairing.