Everyone inside every building is transported to a dungeon where they have to survive floor after floor.

The MC is a depressed anti-social loner with cursed luck. A [Shut in, Hikikomori] who finds himself forced to progress through this new environment.

The one person who never gave up on him is still out there. So he will crawl his way back to them, no matter how much blood he needs to make. Dying is not an option. Not until he meets them again.

Where other's have swords and magic.

MC's cursed luck left him with [Alchemy]

[Expect a ruthless MC that prefers to be alone. Struggling and Despairing deeper and deeper as time passes.]