I've always felt that Gaijan was a sort of parable for depression. I'm sure other mental illnesses can be included, but seeing as I am afflicted with depression, I see that connection most of all.

Nara is afraid of the magic inside of her, and hides it away. She does not understand the what, the how, the when, or the why. Suddenly she is not able to control it any longer, and it destroys everything she ever loved. Depression can manifest in many different ways, and often drives the afflicted to destructive behaviors. It is also very isolating.

Gaijan represents someone in the afflicted person's life that helps. He sees her and knows that something is wrong. He is compassionate, and knows that it is not her choice. Nara thinks it would be better to just give up and not try anymore. Suicide can be seen as a means of escape. 

Gaijan does not give up. A solution, but not the best one, is found in the pillar of crystal. I equate this to the trial and error of finding what works to control the depression. Medication, therapy, exercise, and other coping mechanisms have been used to combat this mental illness. Sometimes the first medication does not work, or has side affects that don't make it worth taking it. Dosage can be adjusted or a new treatment could be suggested. 

The talisman represents a treatment that actually works. There are still side affects (Nara suffers memory loss and nightmares) but they are seen as tolerable compared to the alternative. Nara can never go back to how things were. Dealing with any kind of illness changes a person.

Through all of this Gaijan never leaves. He provides a way for Nara to begin a new life. All the while Nara questions why he would stay. She starts to have struggles dealing with her past, and Gaijan helps her to find more answers by taking her back to where it began.

Outside influences (Daro) make the treatment (the talisman) ineffective, and the magic becomes overwhelming. Again Nara contemplates ending it, and almost succeeds. Gaijan guides her back, and Nara finds a new perspective, a new way to deal, and uses it to her advantage.

Everybody needs a Gaijan in their life. The most important first step is to let them in. It can be a family member, a friend, anyone. Your Gaijan won't give  up, and neither should you. To all those Gaijan-like people out there, thank you. Thank you for never giving up or giving in, for going through all the highs and the lows with your own Nara, and for always having a compassionate heart. 

Whichever role you may fall into, or even if you don't struggle with illness or have someone in your life that does, know that you are loved, you are needed, and that you matter. You always did, and you always will.