(This is a long message, but I hope you'll bear with me.)
You... I have a lot of things to say, actually. I just don't know how to word them to you. First of all, I love how you portrayed Illumi's character in Null. Simply put, it was superb and accurate (in my opinion).
Second of all, Yulli is a masterpiece in terms of characterization (again, in my opinion). That girl is very well-made and done, I must say. But most of all... Your writing style and story sequencing are beautiful.
It's been such a long while since I had last read a book that has a writing style similar to yours. And I'm sure that it would be a while until the time finally came where I would read another like it.
Seriously speaking, you need more followers and reads for creating such a gem of a fanfiction.
On another note, if you don't mind me asking, are you planning on making a sequel?