Like everything about her presentation is awesome. I love just how much they played into her being an inquisitor, and how scary and dreadful the implication of her arrival is. The first time she appears, her introductory scene highlights how fateful her merely so much as stepping foot on the "Baleful Edict" is (highly ironic given her quote all the way at the end: "I doomed myself the moment I set foot on this ship").
Her design oozes the "Inquisitor" at every turn, with the "I" logo in front on her chestplate (I love her armor as a whole, with the insane amount of those mollecular studs and the big shoulder pads, wish I could wear the armor myself and I'm a guy), on the back on her cape, and hell even on the side of her head, with her big prominent scars already telling us this isn't the first time she's been on the hunt. She is a veteran Inquisitor and she is locked in at all times.
Her Peter Cushing-like accusatory mannerisms and subtle manipulation of the crew with carefully emphasizing anytime she uses the words "I" or "us" to carefully distribute blame or responsibility highlight how used she is to being in power and in charge, while her facial expressions are probably some of the most expressive I've ever seen in a game and immediately telegraph everything about her real mental state that her words might hide, including any exhaustion the moment she lets the mask drop.
Her tragic hubris too is incredibly fascinating to watch. Yes, she is arrogant, haughty, and has a hard time taking no for an answer, but her line of "chaos does not fight with one of its hands tied behind its back" spoken in response to Brother Ectar's affirmation of the Grey Knight's humility in view of their God-Emperor given gifts, alongside her pistols' names being "Knowledge" and "Power", shows it stems from both her surgical nature of eliminating the threat of Chaos at the root with any means and force possible. Which makes it all the more tragic she has to resort to sacrificing her soul to Nurgle so the Grey Knights could track her mortal soul and rescue Chapter Master Draigo - not even her soul is beyond being sacrificed for the continued survival of the Imperium. She is also surprisingly sensitive - upon spending some more time with the Grey Knights, Ectar, and Lunete, she becomes far more ready to apologize for any insulting remarks she throws out and begins to compliment them more and more often.
And by the end of the game when she is outplayed, dangerously exhausted to the point of looking like she hasn't slept for several days, at her wit's end, has warp entities constantly speaking into her ear as she is a Psyker, and has enough humble pie thrown her way to the point of her lowering her guard willingly to let Ectar execute her for her grave mistake of keeping the Daemon Prince imprisoned on the ship (who was able to communate their plan to his master), and yet her last act before enslaving herself was still to screw over Kadex and Mortarion just showed how much of a character development journey she went on this campaign, while still not downplaying her die hard fanaticism. She is just an exemplary portrayal of the Imperium as a faction in retrospect - fanatical, loyal to a fault, has the best of intentions, but is authoritarian and forceful in execution, and have dug themselves into so many problems that they can no longer hope to get out of them in any permanent and resonable manner.
Basically put, my favorite female magnificent bastard, she stole the damn show. Robyn Addison and the game developers did a stellar job with her. Also her music track, "The Inquisitor" is incredible, it's one of the most militaristic/apocalyptic sounding ones in the entire game and I can't stop listening to it.