Sword Art Online Progressive 6 (Light Novel)

"First published in Japan in 2018 by Kadokawa Corporation, Tokyo."--title page verso.
At long last, Kirito and
Asuna have reunited with Kizmel the dark elf. But the happy reunion doesn't last
for long. With remaining keys to collect, the appearance of AI that seem a
little too lifelike, and a "secret quest" to deal with, Kirito and Asuna will
have their hands full as they attempt to clear the sixth floor in one
piece!