The story and preview images for Episode 6 of the TV anime Backstabbed in a Backwater Dungeon: My Trusted Companions Tried to Kill Me, but Thanks to the Gift of an Unlimited Gacha I Got LVL 9999 Friends and Am Out for Revenge on My Former Party Members and the World (JP: 信じていた仲間達にダンジョン奥地で殺されかけたがギフト『無限ガチャ』でレベル9999の仲間達を手に入れて元パーティーメンバーと世界に復讐＆『ざまぁ！』します) have been revealed. This episode will air on Friday, November 7 at 11:30 PM (JST), and will later be available on various international streaming platforms.

Episode 6 Story

Aiming for further rank advancement, Light and his party consider taking on a quest to hunt down the notorious “Adventurer Killer,” who targets humans.
At that moment, a spatial distortion suddenly appears in their inn room—out of it emerges a battered and bloodied Mia.

Introduction

Long ago, the goddess created nine races.
Among them, the weakest and most ridiculed were the humans.

A human boy named Light was fortunate enough to be welcomed into a party composed of members from all nine races, the group known as The Gathering of Races.
For a time, he enjoyed days of happiness...
but it was nothing more than a fleeting illusion.

What awaited him was betrayal within the world’s greatest and most dreadful dungeon:
the Abyss.

Having survived the depths of the Abyss, Light discovered the true power of his divine gift:
“Infinite Gacha.”

From the depths of despair, he rises again.
What Light will build is the strongest kingdom of all.
Armed with the one-of-a-kind gift, Infinite Gacha, a world-shaking tale of vengeance begins!!

Source : Backstabbed in a Backwater Dungeon Official Web Site