@saphira209 each chapter there is time passage, and its not the same chapter every week
1 - pillars fighting Muzan and discovering the invisible world, while time is passing
2 - main gang joins the fight, Tanjiro is hurt, Nezuko brakes free, while time is passing
3 - some pillars fall, they discover the red blades, while time is passing
4 - pillars are defeated and main gang are defeated, Tanjiro recovers and is alone now, while time is passing
5 - Nezuko gets closer and closer, Tanjiro almost dies but the last pillar saves him, snake dude is on the fight again, while time is passing
6 - Muzan finds out about all poisons inside him and tries to run away, changing the hole fighting structure from standing still to a moving battle, giving Muzan a huge advantage, at same time that Tanjiro comes closer and closer to "dance forever", while time is passing
7 - Main gang is back, Muzan lost most of its power because of the drug, Nezuko is probably getting on the scene on this chapter or the next, while time is passing
At every single chapter there is a change on the fight dynamic, or on the characters fighting and there is a
literal countdown to the
climax its not the same every chapter.