Synopsis (From Novelupdates):

Popular for being filled with bugs, the virtual-reality game New Communicate Online (a.k.a. Nekomimi Neko Offline).

A die-hard fan of the game, Sagara Souma, is sent to the game world from the power of a mysterious device.

Though surprised by the sudden turn of events, Souma conveniently knows the laws of the world.

Mastering every bug, using the game’s logic against it, he is soon known as “Maverick Swordsman Souma.”

Raw: https://ncode.syosetu.com/n9078bd/

Glossary:

Prologue
Chapter 1-3: Ventriloquism Potion
Chapter 4-5: The man called Reinhardt
Chapter 6: Nekomimi Neko Offline
Chapter 7-8: Shortcut
Chapter 9-10: Hunt
Chapter 11: Train-chan
Chapter 12-13: Prideful Man
Chapter 14-15: To the depths of the earth
Chapter 16: Above the ones that never give up