Mountain Waist Seal

"Doctor, seventeen seconds left."

Shade reminded him again, but he had already relaxed. Holding the sword, he watched the Flame Demon's body gradually vanish from the distant platform while the flames around the doctor grew ever stronger.

Finally, with ten seconds remaining before the doctor had to step back through that door, the Flame Demon on the central platform within the mountain hollow vanished completely.

The doctor shook his restored right hand, and the flames on his body gradually died out. Smiling, he turned to Shade, only to see Shade staring behind him in shock.

Doctor Schneider merely felt something flying swiftly past his face. Then he saw a black stone covered in crimson cracks rush toward Shade's heart.

Shade instinctively swung the longsword in his hand forward. At that moment, he felt as though the sword were guiding his hand, and he pierced the black stone with flawless precision.

The stone was impaled on the blade. The fiery crimson cracks on its surface flickered a few times, then it stopped moving entirely.

"This is the Flame Demon's heart. Yes, it's part of the Flame Demon itself, not the Evil Spirit Demon. I didn't expect an imitated Flame Demon to have an organ like this too. Wait."

The doctor reached out and touched the stone, which still radiated residual warmth:

"Just a Flame Demon heart. There's no other power left in it. Put it in the bottle from the suitcase, the one I labeled. Oh, there isn't enough time."

The doctor patted Shade's shoulder, then jogged into the half-open door.

With a clang, the wooden door with its metal base vanished, and the metal key fell onto the stone platform. At the same time, the two Fireballs the doctor had summoned for light disappeared with him.

The hollow within the