Solitary Sky and Dark Clouds

The protagonist, Lynch, is an ordinary modern social animal. After an unexpected sudden death, his soul is captured by a mysterious "system" and involved in a cruel war that spans countless planes. The first world he came to was the world of Outpost 73 located on the "Abyss Front". This is an apocalyptic world where resources are exhausted, laws are broken, and monsters from the abyss are constantly eroding. Humanity has built its last fortress here and is carrying out desperate resistance. However, Lynch soon discovered that the so-called "system" seemed incomplete and full of unknown mysteries and faults. He not only has to face the deadly dangers everywhere in this world - abyss monsters, radiation, hunger, madness, but also faces threats from other "players" or "higher-dimensional beings". In this world, survival itself is a countdown to a race against death. Lynch must use his identity as a "traveler" and the "broken system" that sometimes doesn't work to fight his way through this cruel arena and uncover the truth hidden behind the "abyss."