I would just like to say one thing to you.
You are fucking amazing!

Your review on my fanfiction, Twisted, was absolutely amazing. You have no idea how much I appreciate that. As for your question... hehehe... It's pathetic, but I shall tell you the truth. Twisted was built completely on an impulse. I was bored, so I was like "Let's write a new fanfiction!" So, in tune with that idea, I watched a few hours of Inu-Yasha that were on my DVR for inspiration. Those episodes just happened to be the ones where he turned youkai, mostly. That was where it came from, and it progressed from there. I did not plot Twisted out at the point, I had no idea where it was going, and I half expected it to never hit the internet, let alone Dokuga. Now that I know I will be continuing the story, I've begun to plot. So, for your question (...was there another reason why Inu chose to turn full demon or was it as he kept saying from the beginning that was what he wanted the jewel for?), the short answer is simple.

I have no idea. -dies of humiliation-

From the way my mind is going now, there will be a deeper meaning to why he did wish to transform. But the details are hazy, fuzzy, and incomplete. Anything I would tell you is a spoiler - but you ask, so I will give you (and anyone who happens to come across this) what is going through my mind.

InuYasha has always... yearned to be accepted, by both races he belongs to. And it has been stated in the manga/anime that InuYasha's blood is not stable on any level and that, I assume, his brain is always torn in between two different sets of instincts. Imagine the headaches, the confusion, the torn emotions... being one would silence the chaos - put him at peace. InuYasha has always wanted to be strong, like Sesshomaru and his Father, which is another incentive to choosing being demon over human. But, also, he assumed that if he were to take a demonic life, he would be in control. Turns out that he isn't. His whole plan backfired on him, and he's barely hanging onto sanity at this point. And his mind isn't quiet either - he's got his smart ass "human" in his head commenting on everything he does.

Most likely, there will be even more reasons, but that's what I have in my head at the moment. Thank you for reading, reviewing like the awesome person you are, and dealing with my insanity!

I hope to talk to you, or at least catch another review from you, later!

Hiyooooo!!
So sorry i've only been able to reply now, i've having recurring bouts of the flu (flu season here you see)
I've been feeling ok for today though how have you been?
I really wanted to update some of the stories and move them here at dokuga (especially since single spark is closing-a poor shame really)
well hope to hear from you soon!
dwX