What happened in the novel?
The old woman took the demon to a false location (it wasn't really the stone from the pact or whatever) and Keira had already warned her beforehand that the other "sister" would arrive. (〜￣△￣)〜
Then when she tries to kill old lady Keira suddenly shows up like "hello motherfucker" (๑•ㅂ•)و✧
And there's a little fight, nothing like what was shown in the manga (⊙…⊙ )
The idiot father arrives and helps subdue the demon from what I remember
For more information you can search on Google for spoilers ヾ(❀╹◡╹)ﾉ~
Keira singlehandedly defeat Cossette and Ragibach was imprisoned in the demon world that she can't escape for her whole life. That's it,no romance. She travel to the magic tower to tell Erez that her father has his memories back even before their bet so Erez can no longer take her father's soul.
Yes
It's so different from the novel (⊙…⊙ )