For those who want to read ahead of the manga, the original light novel is available through J-Novel Club . Media Adaptation

Shinjiteita Nakama-tachi ni Dungeon Okuchi de Korosarekaketa ga Gift "Mugen Gacha" de Level 9999 no Nakama-tachi wo Te ni Irete Moto Party Member to Sekai ni Fukushuu & "Zamaa!" Shimasu!

Shinjiteita Nakama-tachi ni Dungeon Okuchi de Korosare Kaketa ga Gift "Mugen Gacha" de Kyoushuu Nakama wo Hand ni Irete Fukushuu & "Zamaa!" Shimasu —often shortened to —is a must-read. The Premise: A Brutal Betrayal

The title you are looking for is usually translated as: "I Was Almost Killed by My Trusted Companions, So I Banished Them from the Holy Land, but Then I Received a Gift from God." (Japanese: Shinjiteita Nakama ni Dungeon Okuchi de Korosarekaketa kedo Gift wo Moraishita ).