This was a great addition to the SWTOR universe! We get to see Satale Shan, Jace Malcom, Theron Shan, Gnost-Dural, and the inner workings of the SIS. 
 The only real hiccup, in my opinion, was Teff'ith. She was unnecessary and annoying, thank god she wasn't Theron's paramour. Her constant broken Basic (the 'we' thing doesn't bother me) was awful, but then we discover she can fake Imperial accents and speak perfect Basic and just chooses not to. No thank you! 
 Annihilation's story takes place just after the Ilum plot in The Old Republic MMO, following Theron as the Republic attempts to take down a lethal superweapon called the Ascendant Spear, which is controlled by a Jedi-turned-Sith named Darth Karrid. (Can we have the Falleen as a species option in SWTOR now? Please?) This is a definite improvement over Revan, Drew's other TOR novel.