The Strained Coordination

My notebook contains several observations I still hadn't deciphered, even after eight years.

One of them is this—'The strongest can sometimes become weaker when placed together.'

It had remained a hypothesis, with no chance to test it. Humanity had only five people who could serve as test subjects.

That test is about to begin. Worst of all, it will happen during the actual battle.

◇

Just before we reached the bottom of the grand staircase, we crouched low at the final landing and looked down over the hall.

A circular cavern, roughly one hundred meters across. The ceiling was too dark to see. In the center, a shadow like a crouching mountain of rock breathed slowly.

It had two heads.

"Supplement. Observation report. The blinking cycles of the right and left heads do not match. Their breathing is also independent. As hypothesized, there are two minds. In other words, we should regard that as not one creature, but 'two creatures working together.' That's all."

"Night Crow-kun, what about the retreat route?"...