With expansion after expansion, the Research Institute's main complex had grown from the former Kara Organization base underground to cover an area spanning more than a dozen kilometers.
Besides hundreds of researchers, the institute housed large numbers of volunteers and prisoners. Add in the support staff and various guards, and the total population inside the Research Institute exceeded ten thousand.
Laboratories, warehouses, cells, residences, testing areas, living quarters, quarantine zones, and more—all together, they made the Research Institute look more like a bustling city than a secret Akatsuki Organization base.
The Research Institute's existence was no secret in the Shinobi World.
Never mind the large-scale prisoner transfers that had taken place earlier; the sheer quantity of equipment, research supplies, and daily necessities being transported there was impossible to conceal.
As a result, the major shinobi villages and powers in the Shinobi World, along with the black-market forces operating in the shadows, all knew about the Akatsuki Organization's enormous research institute. But cowed by A's might, they all turned a blind eye and pretended not to know.
That was also why so many shinobi from various villages were able to seek out the Research Institute and volunteer for its experiments.
About forty kilometers from the institute's main complex, deep in the mountains, stood another heavily guarded fortress.
Only a handful of people at the Research Institute knew about this secret fortress, and the hidden stronghold deep in the mountains had almost no contact with the outside world.
Late at night.
Amid a rush of wind, several figures landed steadily in front of the fortress nestled in the mountains.
Looking at the quiet fortress before her, Delta planted her hands on her hips and asked bluntly, "Hey, is this the place?"
Ranmaru, who had followed her there, nodded. "Yeah, this should be