User blog comment:FairyRaven/Fairy Tail Chapter 406: The Girl Within the Crystal, Review and Commentary/@comment-25111584-20141027131819/@comment-25111584-20141027201638

No, that'd make sense for 'FT's darkness', but make it hard to use LH as a weapon. More on the lines of ... how should I put it? ... Hmmm:
 * Mavis uses Destiny Bond on Dark Entity.
 * Precht, Warrod & Yury seal Mavis in a stasis chamber.
 * Dark Entity is sent into stasis.

Something along those lines. She wakes up, it wakes up, but her death will release it from the bond, rather than kill it, so it'll come after her.

/me floats to dreamland. (~._.)~

Would be fun if the Dark Entity was the one which actually cursed Zeref's body instead of Zeref just losing control of his Magic, maybe without Zeref's knowledge. An uber-powerful creature which will require Zeref to come to FT's aid. I mean, come on, after looking at the poor guy, one can't but wish there was some way we could have Zeref team up with FT. It could also be used to introduce dark and high fantasy themes into FT (yeah, I wish >.>), something on that line. Maybe, in F. Rogue's timeline, the Dark Entity was responsible for his corruption, many possibilities. Not some kind of Satan though, that'd be boring. With all the talk of Lucy getting the One Magic (please, no) someday, maybe we could have a creature from before Magic, which can be affected by Magic, but not destroted by it. That'd be a good opponent for the magic world ... Curses too, before somebody says that. >.>

/me floats back to reality. ~(._.~)

Yup, not happening. Mashima not gonna introduce high fantasy or try to make the manga darker.