“Shinji – after the events of Darkfall – is particularly interested in what resides within this decrepit cave, believing the Eternal Chasm contains clues regarding the fate of his own father. Whether to aid your prince in his investigation, or to simply test your mettle against a huge array of threats and environments, the mouth of the chasm is eager to swallow all visitors and cast them down into madness. This vast map, ripe for exploration, is littered with nodes that render adventurers into a dream-like state, eliciting visions of what lies ahead. From fiery pits and voracious volcanos, to spine-chilling snow lands and sea-faring shenanigans, the Eternal Chasm is teeming with promising rewards and devious challenges to test yourself against, ever increasing in difficulty as you progress.”
Skill Cultivation Books, Equipment Blueprints, Duskcloud Nyx Treasures, and purple gear top the list of loot inside the dungeon. My.com says only two of the dungeons modes are unlocked at the moment; three more will be opened up in later patches.
Source: Official site