First, I looked at the research on Demonized Beasts.
At the beginning of the apocalypse, Tang Yu had heard of an army dispatching special forces into the Abyssal Rifts, never to return.
After the establishment of the Demon Bureau, this became one of many major undertakings.
As the most important subject of research.
"Apocalypse Calendar January 19th, Operation 'Submarine Abyss' commenced, with Special Combat Teams advancing below the Abyssal Rift."
"Apocalypse Calendar February 1st, the three squads dispatched earlier have not returned."
"Apocalypse Calendar February 13th, the Council decided to shift the focus of the investigation."
…
"Apocalypse Calendar March 1st, a full sweep of Abyssal Rift Number 17 was conducted, and a base was established underground."
