Kimi finally reached the location of the other upper rank demon, which was upper rank 4, Hantengu.
They were in a large field. Hantengu was chasing a few villagers from the swordsmith village. Tanjiro had collapsed on the ground, most likely from exhaustion. Genya was up on the cliff at the edge of the field, and Nezuko was nowhere to be seen.
"I guess it's up to me to finish the job," Kimi thought.
Hantengu appeared to have been decapitated, but Kimi sensed that the real main body was actually hiding inside of what appeared to be the main body. Kimi concentrated hard to find the exact location of the real main body.
"I see," Kimi thought. "It's in the heart."
"Ice Breathing, fifth form," Kimi breathed deeply. "Freezing blade!"
Kimi's sword extended, and was temporarily enhanced with ice. At what appeared to be the speed of light, Kimi rushed toward Hantengu and swung his sword at the neck of the demon's true main body with all of his strength. Kimi managed to decapitate it, and it crumbled to dust.
Both upper rank demons that attacked the swordsmith village had now been defeated.