The Gatekeepers who have proven to be both awe inspiring and intimidating.
Asuna having a dream about Shun when suddenly his arm falls off.
Imagine being a 14 year old, who's trapped in an underground cave and given a choice to either: A. go back the way you came, knowing there are armed men waiting to possibly kill you. B. follow your teacher (who's seemingly lost his mind) beneath a subterranean lake without any sort of diving equipment.
Made worse when Morisaki makes the choice for her, by pulling her beneath the water along with him. Asuna begins to panic, believing she's about to drown.
The Izoku. Deformed shadow creatures with glowing eyes that appear in the dark, or anywhere there's shadow.
Asuna's first night in Argatha ends with her being paralyzed in her sleep by an invisible Izuko. All you see are footprints approaching her, 'til it presses one down on her chest to slowly force the air out of her lungs. Try as she might, she's unable to draw a breath, causing her to begin hyperventilating. Mimi saves her by scaring it away.
They kidnapped both Mana and Asuna to. EAT. THEM. They'll stop at nothing to catch an "impure" human, chasing their prey through the underworld until it's exhausted. It gets worse when Asuna is all alone. One Izoku gets her by the neck and was close to SQUEEZING the life out of her.
Morisaki. Put. A Knife. To. A. CHILD'S THROAT!.
And even before that Morisaki was all for using Asuna's body as a vessel for Lisa's soul.
The Gate of Life and Death can only return life with the expense of another's. To even get there, one has to climb down a very tall sheer cliff.
The Arch Angels are willing to kill children if it means getting into Agartha.
