Leonard Churchill glanced at them and then beckoned Seven Brown to leave.
After watching the two exhausted individuals leave, Kelson and the others finally let out a sigh of relief.
...
Leonard and Seven descended, making their way to the second floor, where the rabbit monster had previously concealed itself.
Using the password they obtained earlier, they unlocked the Mechanical Secret Box.
The contents of the box went along with Leonard's conjecture.
Inside was a vial of green potion.
The Enlightenment Display identified it as a Titan Distortion Inhibitor.
The effect is to suppress the runaway state of a specified Extraordinary Trait.
In other words, it's a strategy to indirectly weaken the "Undying Feature".
Obviously, this is a prop specifically designed for the final BOSS fight.
This is what the Alternate Dimension gives to ordinary adventurers after they discover hidden plots, to increase the probability of monster-slaying.
