Spoilers, kind of!
First off, glad you enjoyed it!
I actually expected everyone who reads it to know Doan is going to die. It's an absolute really, kind of like knowing a ball will fall if tossed in the air. What mattered was how, when, and why. This woman played him the entire time, making a show of preparing him to defend her against a demon. At the end he dies thinking that he was at least doing what was right, protecting someone against a greater evil. I think that's the real tragedy, not knowing your sacrifie is meaningless.
I also like to think that Kali has a small shred of humanity to give him a vague warning at the outset. Or you can say she does it to gaurantee her champion is committed to the cause and won't try to back out. I picture her as a playwright and actor who is totally commited to topping the last show, adding more and more, and willing to sacrifice other's in her endeavor. The show must go on!
As for Doan, that name was kind of taken at the spur of the moment really. I also kinda stole it from the old man in the dome in the future. The name just seemed like it was fit for him though and I couldn't stand changing it to something else. Is there a weighty past to the name Doan that I am crazy oblivious too?
Again, glad you enjoyed it and you can expect more in the future!