Backstabbed in a Backwater Dungeon vol 09 (manga)

Written by Shisui Meikyou
Art by Takashi Ohmae, tef
Cover by Takashi Ohmae, tef

Light and his mighty Level 9,999 party members chase Sionne down into her dungeon laboratory! Before they go, though, Light swings by his Card Repository to stock up…and prepare a special surprise for the diabolical dark elf. An ambush by the sinister Blade of the Isles turns out to be a mere speed bump along Light’s path into the depths of Sionne’s dungeon—and the next step in his revenge plot!

Full Title: 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 (Manga)