Great stuff. The main theme in the Lost Children chapter seems to be escapism. If Jill turns to being a Elf like Rosine she'll be able to escape her life of beatings and abuse for a simple life of simple pleasures. A life of "fun" where you can fly into the sky at will and have no real worries. Apparently even death isn't a fear, as the Mist Valley Elves seem to take it with a smile on their faces. But, at the same time you lose your humanity, which was greatly shown when one of the cocoon broke showing a mass of a creature that is definitely not human.
I also thought it was brilliant writing how Rosine pointed out that "humans always play at war.....The funny thing is we are only PLAYING HUMAN. Yet Jill, the human, hates it so much." Just....great dialogue. And, then Jill commenting on Guts appearing as more of terrifying monster....just great.
Loving this arc so far. It may be because I'm using Dark Horse translations here, but I think the writing has gotten even better.