World After The Fall (Manhwa) Vol 01 (Mature)

A mysterious tower one day appeared in the skies - a beacon of chaos and apocalypse. The heroic Walkers cleared its floors to save humanity, until the Regression Stone was discovered and slowly everyone left. Once the last Walker reached floor 100, he no longer knew what to believe... Ize Press
(W) Singnsong (A) S-Cynan, Undead Gamja