Dr. Karin Chakwas

Doctor Chakwas is the human doctor of the SSV Normandy. She enlisted in the Alliance soon after she graduated from medical school, seeking "exotic adventure", though she quickly realized that military life was not as romantic as she had imagined it to be. However, she stayed with the Alliance in order to do her duty and serve humanity. Though she sometimes considers starting her own private practice, or going to work at a medical center on one of the colonies, she feels that "there is something special about working on soldiers", and believes she would be abandoning them if she did not stay.

Like most Alliance doctors, she has taken courses in alien biology, enabling her to treat the non-human crew members, particularly Liara. Commander Shepard can replenish the squad's medi-gel stocks from the infirmary where she is usually working.

Doctor Chakwas is voiced by Carolyn Seymour.

Shepard encounters Doctor Chakwas when she and Corporal Jenkins are chatting outside the comm room. The doctor finds Jenkins amusing - she teases that the 'action' he craves usually ends with her patching soldiers up in the medical room. After the mission on Eden Prime, when the Prothean Beacon knocks Shepard unconscious, Kaidan and Ashley carry the commander back to the Normandy to be treated by Doctor Chakwas, because she has more experience than the civilian clinics on Eden Prime. She has a very calm bedside manner, assuring Shepard that everything looks normal, though she is perturbed by the commander's vision and decides to add it to her report.

Shepard can talk to Doctor Chakwas later. She has worked with Captain Anderson on several missions, and respects his judgment: "he knows when to let things slide and when to crack the whip." The commander can also ask how well she knows Lieutenant Alenko, but Chakwas responds that she hasn't worked with him before. She can offer an explanation of the medical problems L2 biotics suffer, which provides some background for assignments later on.

After the mutiny, Doctor Chakwas says it is strange being a fugitive from the Alliance. She tells Shepard that the crew has sacrificed everything for the commander's mission: "don't let us down."

Mass Effect 2
Dr. Chakwas is present on the Normandy when it is destroyed by the Collectors. She managed to escape the ship via escape pods, along with several crewmembers. After Shepard's death, the Alliance reassigned the crew to different postings. Chakwas was posted at the Mars Naval Medical Center. Missing the comfort of a starship, Chakwas joined up with Cerberus, getting a position on to SSV Normandy SR-2 and can be found in the Medical Lab. She explains that she's not working for Cerberus, but for her old Commander, in order to assist in the fight against the Collectors. She makes it clear that she has no regret, having lived through the liberation of Shanxi, the Skyllian Blitz and more.

She has a personal side quest (Serrice Ice Brandy) that involves buying her a bottle of liquor on Omega (the bottle can also be bought at the Darkstar Lounge on the Citadel in the Zakera Wards). It's to replace the bottle she had on the SSV Normandy that she regretted never opening. Once Shepard makes the purchase and returns it to her, she'll invite them to open it with her. Some time later, a drunk Dr. Chakwas is shown relating an anecdote about Lt. Jenkins and one of Alliance squadmates in Mass Effect. It is during this event that the player can learn why Dr. Chakwas really joined Cerberus. She joined because Joker would always have Vrolik syndrome and because of that he would always need her help, even if he would never admit it. After the conversation, Dr. Chakwas is found resting on one of the medical beds.

Later in the game, Dr. Chakwas and the rest of the Normady SR-2's crew are abducted by the Collectors and taken to their base. If Shepard immediately commences the suicide mission to rescue the crew and destroy the Collectors' base, he will find Dr. Chakwas with the rest of the crew trapped in pods inside the Collector's base, and manage to free them all before they are processed alive by the Collectors. However, if Shepard delays the suicide mission, depending on how long the mission is delayed, his squad will arrive on the base just in time to save Dr. Chakwas and a progressively smaller number of the Normandy's crew. If you delay the mission at all, she will be upset at the prospect of having to watch her crewmates be dissolved alive. The longer you take to start the suicide mission, the angrier she gets when you find her. Eventually, you will arrive on the Collector Base just in time to save only Dr. Chakwas (despite showing generic crew in the background).

In any case, Shepard will then choose whether or not to allocate a squad members to escort Dr. Chakwas and any other survivors back to the Normandy. If Shepard chooses a loyal squad member to escort Dr. Chakwas back, they will safely return to the Normandy and evacuate the system at the end of the mission. However, if Shepard decides not to assign a squadmate to the task, Dr. Chakwas and any other survivors will be killed en route to the Normandy.

E-Mail from Dr. Chakwas, header Healing of your facial scars
From: Chief Medical Officer Chakwas

Commander, 

''I've done further investigation regarding your facial scaring, and the old adage of "mind over matter" holds true. Negative attitudes and aggressive acts create adverse reactions with your cybenetic implants, while peaceful thoughts and compassionate actions promote healing. If you maintain a positive outlook, I believe your facial scarring will heal on its own. Otherwise, there is surgical equipment we could use to insulate your cybernetic implants and accelerate your healing regardless of your mental outlook.''

I've updated plans for the new medical equipment to your research terminal in the tech lab.

Sincerely,  Chakwas

Trivia

 * 'Chakwas' is an anagram of 'hacksaw'.
 * Carolyn Seymour also provided additional voices for BioWare's Star Wars: The Old Republic and Dragon Age: Origins.